Alert-BDI: BDI Model with Adaptive Alertness through Situational Awareness

In this paper, we address the problems faced by a group of agents that possess situational awareness, but lack a security mechanism, by the introduction of a adaptive risk management system. The Belief-Desire-Intention (BDI) architecture lacks a framework that would facilitate an adaptive risk management system that uses the situational awareness of the agents. We extend the BDI architecture with the concept of adaptive alertness. Agents can modify their level of alertness by monitoring the risks faced by them and by their peers. Alert-BDI enables the agents to detect and assess the risks faced by them in an efficient manner, thereby increasing operational efficiency and resistance against attacks.Comment: 14 pages, 3 figures. Submitted to ICACCI 2013, Mysore, Indi

Probing the Electronic and Magnetic Properties of Transparent Semiconductor Nanowires using X-ray Absorption Spectroscopic Methods

Control of electron spins in individual magnetically doped semiconductor nanostructures has considerable potential for quantum information processing and storage. The manipulations of dilute magnetic interactions have largely been restricted to low temperatures, limiting their potential technological applications. Among the systems predicted to be ferromagnetic above room temperature, Mn-doped GaN has attracted particular attention, due to its attractive optical and electrical properties. However, the experimental data have been inconsistent, and the origin of the magnetic interactions remains unclear. Furthermore, there has been no demonstration of tuning the dopant exchange interactions within a single nanostructure, which is necessary for the design of nanoscale spin-electronic (spintronic) devices.\par This work demonstrates for the first time intrinsic magnetization of manganese dopants in individual gallium nitride nanowires (NWs) at room temperature, which were synthesised using the chemical vapor deposition method. The results of single nanowire XANES studies using scanning transmission X-ray microscopy along with atomic multiplet calculations confirm that Mn adopts tetrahedral coordination in GaN nanowires and has mixed oxidation state (\ch{Mn^{2+}}/\ch{Mn^{3+}}), with \ch{Mn^{2+}} being in relative majority. Using high-resolution circularly polarized X-ray microscopy imaging, the dependence of the manganese exchange interactions on the NW orientation with respect to the external magnetic field was studied. This study also focused on the importance of X-ray studies on individual nanowires, as in ensemble measurements contribution come from the co-deposition of Mn secondary phases alongside nanowires. This was further confirmed by bulk magnetization measurements, which has shown only residual magnetization. Single nanowire X-ray magnetic circular dichroism indicates intrinsic magnetic ordering of Mn dopants at \SI{300}{\kelvin}. The crystalline anisotropy allows for the control of dilute magnetization in a single NW and the application of bottom-up approaches, such as \textit{in situ} nanowire growth control or targeted positioning of individual NWs, for the design of energy efficient spin-electronic devices.\par The second part of the thesis focuses on the growth mechanism and origin of orbital anisotropy in $\beta$-\ch{Ga2O3} nanowires. Gallium oxide nanostructures with high aspect ratio and variable faceting were synthesized by the chemical vapor deposition method via vapor–solid growth mechanism. Systematic investigation of the growth conditions revealed that the nanowires can be produced under the conditions of high temperature and low precursor flow. The nanowires crystalize as the $\beta$-phase \ch{Ga2O3}, which has the monoclinic crystal structure. Preferred growth was along the [010] direction, as corroborated with lattice-resolved imaging and crystal plane models. The high degree of faceting is discussed in terms of the evolution of the nanowire cross-section morphology, based on the growth rate of the facet boundaries relative to the nanowire surface planes.\par The origin of anisotropy at the molecular and electronic structure levels in individual $\beta$-\ch{Ga2O3} nanowires grown along the crystallographic $b$ direction was studied using linearly polarized X-ray absorption imaging at both gallium L$_3$ and oxygen K edges. The O K-edge spectrum shows significant linear dichroism for the electric field vector of the X-rays oriented parallel and perpendicular to the nanowire long axis. The contributions from the three nonequivalent oxygen sites to the observed spectral anisotropy were elucidated using FDMNES calculations in the framework of the multiple scattering theory. The role of relevant O and Ga orbitals in the linearly polarized O K-edge absorption was determined based on the point group symmetry arguments. The results of this work suggest mixed covalent and ionic character of the Ga-O bond in individual nanowires, with the dominant contribution of O 2\textit{p}$_z$ orbitals to the absorption spectrum for the electric field vector oriented perpendicular, and O 2\textit{p}$_{x,y}$ orbitals for the electric field vector oriented parallel to the nanowire long axis. Gallium 4\textit{p} and \textit{d} orbitals were found to contribute mostly to the antibonding states. These results improve the understanding of the origin of anisotropy in complex transparent metal oxide nanostructures, and could lead to the prediction of physical properties for different nanowire growth directions.\par The understanding of growth mechanism, dopant distribution and electronic origin of crystalline anisotropy within individual semiconductor nanowires is of fundamental importance. It is these structural parameters can dramatically change electronic, magnetic, and optoelectronic properties of the nanowires, and could be building blocks for the future nanodevices

Acyclic Chromatic Index of Chordless Graphs

An acyclic edge coloring of a graph is a proper edge coloring in which there are no bichromatic cycles. The acyclic chromatic index of a graph $G$ denoted by $a'(G)$, is the minimum positive integer $k$ such that $G$ has an acyclic edge coloring with $k$ colors. It has been conjectured by Fiam\v{c}\'{\i}k that $a'(G) \le \Delta+2$ for any graph $G$ with maximum degree $\Delta$. Linear arboricity of a graph $G$, denoted by $la(G)$, is the minimum number of linear forests into which the edges of $G$ can be partitioned. A graph is said to be chordless if no cycle in the graph contains a chord. Every $2$-connected chordless graph is a minimally $2$-connected graph. It was shown by Basavaraju and Chandran that if $G$ is $2$-degenerate, then $a'(G) \le \Delta+1$. Since chordless graphs are also $2$-degenerate, we have $a'(G) \le \Delta+1$ for any chordless graph $G$. Machado, de Figueiredo and Trotignon proved that the chromatic index of a chordless graph is $\Delta$ when $\Delta \ge 3$. They also obtained a polynomial time algorithm to color a chordless graph optimally. We improve this result by proving that the acyclic chromatic index of a chordless graph is $\Delta$, except when $\Delta=2$ and the graph has a cycle, in which case it is $\Delta+1$. We also provide the sketch of a polynomial time algorithm for an optimal acyclic edge coloring of a chordless graph. As a byproduct, we also prove that $la(G) = \lceil \frac{\Delta }{2} \rceil$, unless $G$ has a cycle with $\Delta=2$, in which case $la(G) = \lceil \frac{\Delta+1}{2} \rceil = 2$. To obtain the result on acyclic chromatic index, we prove a structural result on chordless graphs which is a refinement of the structure given by Machado, de Figueiredo and Trotignon for this class of graphs. This might be of independent interest

Breeding chickpea for water limited environments: selection indices and strategies

Chickpea (Cicer arietinum L.) is the one of the most important pulse crops in the world and its production is limited by terminal drought. Unlike conventional breeding for yield, it is more challenging and requires to be measured in terms of its manifestation towards changing performance of a genotype under stress. An evaluation of a panel developed for drought and breeding studies has clearly identified the presence of large variability for drought tolerance. A large number of traits have been screened and it has been inferred that drought susceptibility index is the best way to identify genotypes that have resilience to terminal drought. However, different genotypes possessed various physiological mechanisms to cope with the effects of drought and, hence, provide ample opportunities to breeders to combine them to develop drought-tolerant genotypes. The chickpea genotypes L550, PG112 and ICC92944 have shown higher mean values for yield traits under stress and have desirable terminal drought-tolerant mechanisms for yield and other associated characters such as lower DSI, higher HI, higher BY and higher grain yield. They have, thus, emerged as stable genotypes for yield under stress situations. Though MABC for root traits has been identified, rapid screening techniques using CTD and identification of markers for MSI and RWC to be used for screening segregating generations appears to be promising in north Indian conditions. This is because unlike in south India, drought in the north India develops abruptly after a cold period, giving little time for the root system to respond. Thus, breeding for terminal drought tolerance would require concentrating on these traits too

GWAS meta-analysis of over 29,000 people with epilepsy identifies 26 risk loci and subtype-specific genetic architecture

Epilepsy is a highly heritable disorder affecting over 50 million people worldwide, of which about one-third are resistant to current treatments. Here we report a multi-ancestry genome-wide association study including 29,944 cases, stratified into three broad categories and seven subtypes of epilepsy, and 52,538 controls. We identify 26 genome-wide significant loci, 19 of which are specific to genetic generalized epilepsy (GGE). We implicate 29 likely causal genes underlying these 26 loci. SNP-based heritability analyses show that common variants explain between 39.6% and 90% of genetic risk for GGE and its subtypes. Subtype analysis revealed markedly different genetic architectures between focal and generalized epilepsies. Gene-set analyses of GGE signals implicate synaptic processes in both excitatory and inhibitory neurons in the brain. Prioritized candidate genes overlap with monogenic epilepsy genes and with targets of current antiseizure medications. Finally, we leverage our results to identify alternate drugs with predicted efficacy if repurposed for epilepsy treatment

Genome-wide identification and phenotypic characterization of seizure-associated copy number variations in 741,075 individuals

Copy number variants (CNV) are established risk factors for neurodevelopmental disorders with seizures or epilepsy. With the hypothesis that seizure disorders share genetic risk factors, we pooled CNV data from 10,590 individuals with seizure disorders, 16,109 individuals with clinically validated epilepsy, and 492,324 population controls and identified 25 genome-wide significant loci, 22 of which are novel for seizure disorders, such as deletions at 1p36.33, 1q44, 2p21-p16.3, 3q29, 8p23.3-p23.2, 9p24.3, 10q26.3, 15q11.2, 15q12-q13.1, 16p12.2, 17q21.31, duplications at 2q13, 9q34.3, 16p13.3, 17q12, 19p13.3, 20q13.33, and reciprocal CNVs at 16p11.2, and 22q11.21. Using genetic data from additional 248,751 individuals with 23 neuropsychiatric phenotypes, we explored the pleiotropy of these 25 loci. Finally, in a subset of individuals with epilepsy and detailed clinical data available, we performed phenome-wide association analyses between individual CNVs and clinical annotations categorized through the Human Phenotype Ontology (HPO). For six CNVs, we identified 19 significant associations with specific HPO terms and generated, for all CNVs, phenotype signatures across 17 clinical categories relevant for epileptologists. This is the most comprehensive investigation of CNVs in epilepsy and related seizure disorders, with potential implications for clinical practice

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New Ethical and Clinical Challenges in "Closed-Loop" Neuromodulation.

Neurostimulation provides a new dimension in the treatment of neurologic disorders. For patients with drug-resistant epilepsy, the Responsive Neurostimulation (RNS) System (NeuroPace, Inc.) provides treatment of seizures with a closed-loop device that continuously records brain activity and provides stimulation designed to reduce seizure frequency over time. The presence of a chronic implanted device that can provide an electrographic record of neural activity provides great opportunities for treatment of seizure disorders and neuroscience research. However, our experience with this device indicates that a number of ethical and clinical challenges arise, and these issues may be applicable to neurotechnology developed for other disease states in the future. We present clinical scenarios based on cases from our center that present clinical or ethical dilemmas. The dilemmas revolve around 4 core themes: (1) electroclinical correlation and dissociation; (2) patient concerns about device capabilities; (3) clinician opportunities and burdens; and (4) data ownership and access. Developing a framework for understanding these issues will be critical as closed-loop neuromodulation is applied to a growing range of neuropsychiatric disorders