A study of the variational aspects for the Fock expansion of the solution of hydrogenic atoms in constant magnetic fields

The study of hydrogen in a constant magnetic field has been one of the most persistent problems in non-relativistic quantum mechanics. Although it is conceptually one of the simplest problems that one can think of, the non-separability of the Schrodinger Equation containing both a Coulombic term and a constant magnetic term in theHamiltonian has made the problem especially difficult. In this dissertation, we apply a solution in the form of the Fock expansion to this problem. It is shown that the logarithmic terms which are associated with the Fock expansion vanish. We then derive and solve a three term recurrence relation in order to find a set of solutions to this Schrodinger equation. Linear combinations of these Fock solutions which satisfy the physical boundary conditions are found, and at the same time upper bounds for the binding energies are found using the Raleigh-Ritz variational principal. It is shown that these same Fock solutions produce lower bounds for the binding energies when theSchwinger variational principal is employed. Therefore, the energies for bound states of hydrogen in a constant magnetic field can be bracketed from both above and below. We furthermore examine another recent method, that of Kravchenko,Liberman and Johansson[15] for solving the hydrogen atom in a constant magnetic field problem. We show that their method is equivalent to examining an eigenchannel in the R-matrix method of Bohm and Fano, and compare their results to the ones we obtain through variational methods on the Fock solution. We find that their method is both accurate and efficient for calculating the binding energies

Tv-RIO1 – an atypical protein kinase from the parasitic nematode Trichostrongylus vitrinus

Background: Protein kinases are key enzymes that regulate a wide range of cellular processes, including cell-cycle progression, transcription, DNA replication and metabolic functions. These enzymes catalyse the transfer of phosphates to serine, threonine and tyrosine residues, thus playing functional roles in reversible protein phosphorylation. There are two main groups, namely eukaryotic protein kinases (ePKs) and atypical protein kinases (aPKs); RIO kinases belong to the latter group. While there is some information about RIO kinases and their roles in animals, nothing is known about them in parasites. This is the first study to characterise a RIO1 kinase from any parasite. Results: A full-length cDNA (Tv-rio-1) encoding a RIO1 protein kinase (Tv-RIO1) was isolated from the economically important parasitic nematode Trichostrongylus vitrinus (Order Strongylida). The uninterrupted open reading frame (ORF) of 1476 nucleotides encoded a protein of 491 amino acids, containing the characteristic RIO1 motif LVHADLSEYNTL. Tv-rio-1 was transcribed at the highest level in the third-stage larva (L3), and a higher level in adult females than in males. Comparison with homologues from other organisms showed that protein Tv-RIO1 had significant homology to related proteins from a range of metazoans and plants. Amino acid sequence identity was most pronounced in the ATP-binding motif, active site and metal binding loop. Phylogenetic analyses of selected amino acid sequence data revealed Tv-RIO1 to be most closely related to the proteins in the species of Caenorhabditis. A structural model of Tv-RIO1 was constructed and compared with the published crystal structure of RIO1 of Archaeoglobus fulgidus (Af-Rio1). Conclusion: This study provides the first insights into the RIO1 protein kinases of nematodes, and a foundation for further investigations into the biochemical and functional roles of this molecule in biological processes in parasitic nematodes

Continuous monitoring of the lunar or Martian subsurface using on-board pattern recognition and neural processing of Rover geophysical data

The ultimate goal is to create an extraterrestrial unmanned system for subsurface mapping and exploration. Neural networks are to be used to recognize anomalies in the profiles that correspond to potentially exploitable subsurface features. The ground penetrating radar (GPR) techniques are likewise identical. Hence, the preliminary research focus on GPR systems will be directly applicable to seismic systems once such systems can be designed for continuous operation. The original GPR profile may be very complex due to electrical behavior of the background, targets, and antennas, much as the seismic record is made complex by multiple reflections, ghosting, and ringing. Because the format of the GPR data is similar to the format of seismic data, seismic processing software may be applied to GPR data to help enhance the data. A neural network may then be trained to more accurately identify anomalies from the processed record than from the original record

Exquisite Sequence Selectivity with Small Conditional RNAs

Dynamic RNA nanotechnology based on programmable hybridization cascades with small conditional RNAs (scRNAs) offers a promising conceptual framework for engineering programmable conditional regulation in vivo. While single-base substitution (SBS) somatic mutations and single-nucleotide polymorphisms (SNPs) are important markers and drivers of disease, it is unclear whether synthetic RNA signal transducers are sufficiently programmable to accept a cognate RNA input while rejecting single-nucleotide sequence variants. Here, we explore the limits of scRNA programmability, demonstrating isothermal, enzyme-free genotyping of RNA SBS cancer markers and SNPs using scRNAs that execute a conditional hybridization cascade in the presence of a cognate RNA target. Kinetic discrimination can be engineered on a time scale of choice from minutes to days. To discriminate even the most challenging single-nucleotide sequence variants, including those that lead to nearly isoenergetic RNA wobble pairs, competitive inhibition with an unstructured scavenger strand or with other scRNAs provides a simple and effective principle for achieving exquisite sequence selectivity

Charge Conjugation from Space-Time Inversion

We show that the CPT group of the Dirac field emerges naturally from the PT and P (or T) subgroups of the Lorentz group.Comment: 4 pages, no figure

Decomposition of stochastic flows with automorphism of subbundles component

We show that given a $G$-structure $P$ on a differentiable manifold $M$, if the group $G(M)$ of automorphisms of $P$ is big enough, then there exists the quotient of an stochastic flows $phi_t$ by $G(M)$, in the sense that $\phi_t = \xi_t \circ \rho_t$ where $\xi_t \in G(M)$, the remainder $\rho_t$ has derivative which is vertical but transversal to the fibre of $P$. This geometrical context generalizes previous results where $M$ is a Riemannian manifold and $\phi_t$ is decomposed with an isometric component, see Liao \cite{Liao1} and Ruffino \cite{Ruffino}, which in our context corresponds to the particular case of an SO(n)-structure on $M$.Comment: To appear in Stochastics and Dynamics, 201

Experienced tutors' deployment of thinking skills and what might be entailed in enhancing such skills

In the context of research that reports weaknesses in adults' critical thinking skills, the primary aim was to examine adults' use of critical thinking skills that are described in taxonomies and to identify areas for development. Position papers written by an opportunity sample of 32 experienced adult educators formed the data for a descriptive sample survey design intended to reveal participants' use of critical thinking skills. Each 6000-word paper was written during a development programme that supported such skills. A content analysis of the papers revealed that when participants drew on personal and published ideas about learning to derive their proposals for change, they accepted the ideas uncritically, thereby implying that they might find it difficult to help learners to examine ideas critically. The evidence supports research that implies that critical thinking skills are unlikely to develop unless overall course design privileges the development of epistemological understanding (King and Kitchener 1994, Kuhn 1999). A fundamental assumption underlying the study is that this understanding influences effective citizenship and personal development, as well as employability. A proposition that merits attention in future research is that the development of epistemological understanding is largely neglected in current curricula in formal post-16 education

Ascaroside Signaling Is Widely Conserved among Nematodes

Background: Nematodes are among the most successful animals on earth and include important human pathogens, yet little is known about nematode pheromone systems. A group of small molecules called ascarosides has been found to mediate mate finding, aggregation, and developmental diapause in Caenorhabditis elegans, but it is unknown whether ascaroside signaling exists outside of the genus Caenorhabditis. Results: To determine whether ascarosides are used as signaling molecules by other nematode species, we performed a mass spectrometry-based screen for ascarosides in secretions from a variety of both free-living and parasitic (plant, insect, and animal) nematodes. We found that most of the species analyzed, including nematodes from several different clades, produce species-specific ascaroside mixtures. In some cases, ascaroside biosynthesis patterns appear to correlate with phylogeny, whereas in other cases, biosynthesis seems to correlate with lifestyle and ecological niche. We further show that ascarosides mediate distinct nematode behaviors, such as retention, avoidance, and long-range attraction, and that different nematode species respond to distinct, but overlapping, sets of ascarosides. Conclusions: Our findings indicate that nematodes utilize a conserved family of signaling molecules despite having evolved to occupy diverse ecologies. Their structural features and level of conservation are evocative of bacterial quorum sensing, where acyl homoserine lactones (AHLs) are both produced and sensed by many species of gram-negative bacteria. The identification of species-specific ascaroside profiles may enable pheromone-based approaches to interfere with reproduction and survival of parasitic nematodes, which are responsible for significant agricultural losses and many human diseases worldwide

Management der oberen Atemwege beim spontan atmenden Kind: Eine Herausforderung für den Anästhesisten

Zusammenfassung: Partielle und totale Atemwegsobstruktionen treten bei spontan atmenden, bewusstlosen oder anästhesierten Kindern häufig auf und können eine adäquate Sauerstoffversorgung gefährden. Das Offenhalten der oberen Atemwege ist daher die wichtigste und effektivste Maßnahme in dieser Situation: Kinn hochheben ("chin lift"), Unterkiefer nach vorne verschieben ("jaw thrust", Esmarch-Handgriff) und kontinuierlich positiver Atemwegsdruck ("continuous positive airway pressure", CPAP) öffnen nachgewiesenermaßen den Atemweg. Neben diesen einfachen Atemwegsmanövern führen auch verschiedene Lagerungstechniken (Seitenlage oder Rückenlage unter Einnahme der "Schnüffelposition") zu einer besseren Öffnung und Stabilität des oberen Atemweg