Note on a variation of the Schröder-Bernstein problem for fields

summary:In this note we study fields $F$ with the property that the simple transcendental extension $F(u)$ of $F$ is isomorphic to some subfield of $F$ but not isomorphic to $F$. Such a field provides one type of solution of the Schröder-Bernstein problem for fields

A Holder Continuous Nowhere Improvable Function with Derivative Singular Distribution

We present a class of functions $\mathcal{K}$ in $C^0(\R)$ which is variant of the Knopp class of nowhere differentiable functions. We derive estimates which establish \mathcal{K} \sub C^{0,\al}(\R) for 0<\al<1 but no $K \in \mathcal{K}$ is pointwise anywhere improvable to C^{0,\be} for any \be>\al. In particular, all $K$'s are nowhere differentiable with derivatives singular distributions. $\mathcal{K}$ furnishes explicit realizations of the functional analytic result of Berezhnoi. Recently, the author and simulteously others laid the foundations of Vector-Valued Calculus of Variations in $L^\infty$ (Katzourakis), of $L^\infty$-Extremal Quasiconformal maps (Capogna and Raich, Katzourakis) and of Optimal Lipschitz Extensions of maps (Sheffield and Smart). The "Euler-Lagrange PDE" of Calculus of Variations in $L^\infty$ is the nonlinear nondivergence form Aronsson PDE with as special case the $\infty$-Laplacian. Using $\mathcal{K}$, we construct singular solutions for these PDEs. In the scalar case, we partially answered the open $C^1$ regularity problem of Viscosity Solutions to Aronsson's PDE (Katzourakis). In the vector case, the solutions can not be rigorously interpreted by existing PDE theories and justify our new theory of Contact solutions for fully nonlinear systems (Katzourakis). Validity of arguments of our new theory and failure of classical approaches both rely on the properties of $\mathcal{K}$.Comment: 5 figures, accepted to SeMA Journal (2012), to appea

Mulsemedia: State of the art, perspectives, and challenges

Mulsemedia-multiple sensorial media-captures a wide variety of research efforts and applications. This article presents a historic perspective on mulsemedia work and reviews current developments in the area. These take place across the traditional multimedia spectrum-from virtual reality applications to computer games-as well as efforts in the arts, gastronomy, and therapy, to mention a few. We also describe standardization efforts, via the MPEG-V standard, and identify future developments and exciting challenges the community needs to overcome

Charged Vortices in High Temperature Superconductors Probed by NMR

We report a first experimental evidence that a vortex in the high temperature superconductors (HTSC) traps a finite electric charge from the high resolution measurements of the nuclear quadrupole frequencies. In slightly overdoped YBa_2Cu_3O_7 the vortex is negatively charged by trapping electrons, while in underdoped YBa_2Cu_4O_8 it is positively charged by expelling electrons. The sign of the trapped charge is opposite to the sign predicted by the conventional BCS theory. Moreover, in both materials, the deviation of the magnitude of the charge from the theory is also significant. These unexpected features can be attributed to the novel electronic structure of the vortex in HTSC.Comment: 6 pages, 7 figures, to be published in Phys Rev.

A Novel Staphylococcus Podophage Encodes a Unique Lysin with Unusual Modular Design

ABSTRACT Drug-resistant staphylococci, particularly Staphylococcus aureus and Staphylococcus epidermidis, are leading causes of hospital-acquired infections. Bacteriophages and their peptidoglycan hydrolytic enzymes (lysins) are currently being explored as alternatives to conventional antibiotics; however, only a limited diversity of staphylococcal phages and their lysins has yet been characterized. Here, we describe a novel staphylococcal phage and its lysins. Bacteriophage Andhra is the first reported S. epidermidis phage belonging to the family Podoviridae. Andhra possesses an 18,546-nucleotide genome with 20 open reading frames. BLASTp searches revealed that gene product 10 (gp10) and gp14 harbor putative catalytic domains with predicted peptidase and amidase activities, characteristic functions of phage lysins. We purified these proteins and show that both Andhra_gp10 and Andhra_gp14 inhibit growth and degrade cell walls of diverse staphylococci, with Andhra_gp10 exhibiting more robust activity against the panel of cell wall substrates tested. Site-directed mutagenesis of its predicted catalytic residues abrogated the activity of Andhra_gp10, consistent with the presence of a catalytic CHAP domain on its C terminus. The active site location combined with the absence of an SH3b cell wall binding domain distinguishes Andhra_gp10 from the majority of staphylococcal lysins characterized to date. Importantly, close homologs of Andhra_gp10 are present in related staphylococcal podophages, and we propose that these constitute a new class of phage-encoded lysins. Altogether, our results reveal insights into the biology of a rare family of staphylococcal phages while adding to the arsenal of antimicrobials with potential for therapeutic use. IMPORTANCE The spread of antibiotic resistance among bacterial pathogens is inciting a global public health crisis. Drug-resistant Staphylococcus species, especially S. aureus and S. epidermidis, have emerged in both hospital and community settings, underscoring the urgent need for new strategies to combat staphylococcal infections. Bacterial viruses (phages) and the enzymes that they use to degrade bacterial cell walls (lysins) show promise as alternative antimicrobials; however, only a limited variety of staphylococcal phages and their lysins have yet been identified. Here, we report the discovery and characterization of a novel staphylococcal phage, Andhra. We show that Andhra encodes two lysins (Andhra_gp10 and Andhra_gp14) that inhibit growth and degrade the cell walls of diverse staphylococci, including S. aureus and S. epidermidis strains. Andhra and its unique lysins add to the arsenal of antimicrobials with potential for therapeutic use

Analysis of motor dysfunction in Down Syndrome reveals motor neuron degeneration

Down Syndrome (DS) is caused by trisomy of chromosome 21 (Hsa21) and results in a spectrum of phenotypes including learning and memory deficits, and motor dysfunction. It has been hypothesized that an additional copy of a few Hsa21 dosage-sensitive genes causes these phenotypes, but this has been challenged by observations that aneuploidy can cause phenotypes by the mass action of large numbers of genes, with undetectable contributions from individual sequences. The motor abnormalities in DS are relatively understudied-the identity of causative dosage-sensitive genes and the mechanism underpinning the phenotypes are unknown. Using a panel of mouse strains with duplications of regions of mouse chromosomes orthologous to Hsa21 we show that increased dosage of small numbers of genes causes locomotor dysfunction and, moreover, that the Dyrk1a gene is required in three copies to cause the phenotype. Furthermore, we show for the first time a new DS phenotype: loss of motor neurons both in mouse models and, importantly, in humans with DS, that may contribute to locomotor dysfunction

Extensive marine-terminating ice sheets in Europe from 2.5 million years ago

Geometries of Early Pleistocene [2.58 to 0.78 million years (Ma) ago] ice sheets in northwest Europe are poorly constrained but are required to improve our understanding of past ocean-atmosphere-cryosphere coupling. Ice sheets are believed to have changed in their response to orbital forcing, becoming, from about 1.2 Ma ago, volumetrically larger and longer-lived. We present a multiproxy data set for the North Sea, extending to over a kilometer below the present-day seafloor, which demonstrates spatially extensive glaciation of the basin from the earliest Pleistocene. Ice sheets repeatedly entered the North Sea, south of 60°N, in water depths of up to ~250 m from 2.53 Ma ago and subsequently grounded in the center of the basin, in deeper water, from 1.87 Ma ago. Despite lower global ice volumes, these ice sheets were near comparable in spatial extent to those of the Middle and Late Pleistocene but possibly thinner and moving over slippery (low basal resistance) beds

The Management of Disclosure in Children’s Accounts of Domestic Violence: Practices of Telling and Not Telling

Children and young people who experience domestic violence are often represented as passive witnesses, too vulnerable to tell the stories of their own lives. This article reports on findings from a 2 year European research project (Understanding Agency and Resistance Strategies, UNARS) with children and young people in Greece, Italy, Spain and the UK, who had experienced domestic violence. It explores children and young people’s understandings of their own capacity to reflect on and disclose their experiences Extracts from individual interviews with 107 children and young people (age 8–18) were analysed. Three themes are presented, that illustrate children and young people’s strategies for managing disclosure: (1) “Being silenced or choosing silence?”, explores children and young people’s practices of self-silencing; (2) “Managing disclosures: Finding ways to tell” outlines how children and young people value self-expression, and the strategies they use to disclose safely; and in (3) “Speaking with many voices” considers how children and young people’s accounts of their experiences are constituted relationally, and are often polyvocal. The article concludes that children and young people can be articulate, strategic and reflexive communicators, and that good support for families struggling with domestic violence must enable space for children and young people’s voice to be heard. This is possible only in an integrated framework able to encompass multiple layers and perspectives, rather than privileging the adult point of view. Practitioners who work with families affected by domestic violence need to recognize that children and young people are able to reflect on and speak about their experiences. This requires that attention is paid to the complexity of children and young people’s communication practices, and the relational context of those communications

Properties of a Yeast Cytochrome P-450-Containing Enzyme System which Catalyzes the Hydroxylation of Fatty Acids, Alkanes, and Drugs

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65977/1/j.1432-1033.1973.tb02948.x.pd