The Foaming Three-Charge Black Hole

We find a very large set of smooth horizonless geometries that have the same charges and angular momenta as the five-dimensional, maximally-spinning, three-charge, BPS black hole (J^2 = Q^3). Our solutions are constructed using a four-dimensional Gibbons-Hawking base space that has a very large number of two-cycles. The entropy of our solutions is proportional to Q^(1/2). In the same class of solutions we also find microstates corresponding to zero-entropy black rings, and these are related to the microstates of the black hole by continuous deformations.Comment: 14 pages, harvma

The N=2N=2 super W4W_4 algebra and its associated generalized KdV hierarchies

We construct the $N=2$ super $W_4$ algebra as a certain reduction of the second Gel'fand-Dikii bracket on the dual of the Lie superalgebra of $N=1$ super pseudo-differential operators. The algebra is put in manifestly $N=2$ supersymmetric form in terms of three $N=2$ superfields $\Phi_i(X)$, with $\Phi_1$ being the $N=2$ energy momentum tensor and $\Phi_2$ and $\Phi_3$ being conformal spin $2$ and $3$ superfields respectively. A search for integrable hierarchies of the generalized KdV variety with this algebra as Hamiltonian structure gives three solutions, exactly the same number as for the $W_2$ (super KdV) and $W_3$ (super Boussinesq) cases.Comment: 16 pages, LaTeX, UTAS-PHYS-92-3

Handheld computers: Do they support or constrain nursing students at the point -of -care?

Technology has made a significant impact within the healthcare system over recent years. As technology continues to evolve and becomes a major driving force within the healthcare system, so will the need for preparing technologically competent healthcare professionals. Also within the healthcare system, changes such as a decrease in the length of hospital stay, the aging population, and the multi-disease processes of the aging population, presents a challenge to nursing faculty to adequately prepare tomorrows\u27 nurse. One of the most promising technological devices being used by healthcare professionals is the handheld computer or personal digital assistant (PDA). Although the current literature supports the use of the PDA by practicing nurses and nursing students, little is known how to incorporate these devices to support and develop life-long learners; A mixed-method design directed this study. Biemiller & Meichenbaum\u27s Think-Aloud was conducted at the onset and conclusion of the study. A grounded theory approach was utilized to gather data pertaining to PDAs and nursing students. Upon observing the participant accessing the PDA, a semi-structured interview occurred. The last component of data collection was obtained via a tracking system on a nursing focused PDA software program; The results demonstrate that the PDA supports self-regulated/self-directed learning in nursing students. Biemiller & Meichenbaum\u27s Think-Aloud demonstrated that all participants increased in their ability to be self-directed learners at the conclusion of the study. Furthermore, the results demonstrated that students are accessing the PDA in the clinical site, in the classroom, in studying for test/exams, and when completing assignments. Although the age varied for the participants, the method preferred for learning was from the screen; Pintrich\u27s self-regulated learning model was used as a method of determining the extent and progression of identifying self-regulated learners. Again, the results displayed that the PDA supported the participant in becoming self-regulated learners by providing them with a tool that offers precise, current, accurate, and current time information. With the ease of accessing information any time and from anywhere, nursing students have the potential to control what and how learning occurs

Designing talk in social networks: What Facebook teaches about conversation

The easy accessibility, ubiquity, and plurilingualism of popular SNSs such as Facebook have inspired many scholars and practitioners of second language teaching and learning to integrate networked forms of communication into educational contexts such as language classrooms and study abroad programs (e.g., Blattner & Fiori, 2011; Lamy & Zourou, 2013; Mills, 2011; Reinhardt & Ryu, 2013; Reinhardt & Zander, 2011). At the same time, the complex and dynamic patterns of interaction that emerge in these spaces quickly push back upon standard ways of describing conversational genres and communicative competence (Kern, 2014; Lotherington & Ronda, 2014). Drawing from an ecological interactional analysis (Goffman, 1964, 1981a, 1981b, 1986; Kramsch & Whiteside, 2008) of the Facebook communications of three German-speaking academics whose social and professional lives are largely led in English, the authors consider the kinds of symbolic maneuvers required to participate in the translingual conversational flows of SNS-mediated communication. Based on this analysis, this article argues that texts generated through SNS-mediated communication can provide classroom opportunities for critical, stylistically sensitive reflection on the nature of talk in line with multiliteracies approaches

Spatial Variation in the Chemical Composition of Natal Otholiths from a Reef Fish in the Galápagos Islands

Over the past decade, researchers have used variation in the chemical composition of fish otoliths (earstones) to address a number of ecological questions, such as stock assessment and assessing rates of movement of individuals among habitats or life-history stages. However, these methods have yet to be applied successfully to the study of larval connectivity, a major unanswered question in marine ecology. Accomplishing this task requires a reference collection of pre-pelagic natal otoliths and accurate measurement of the chemical signatures of otoliths cores of recruits. We analyzed the chemical composition of natal otoliths from near-term benthic eggs of a damselfish (Stegastes beebei) from all regions of the Galápagos Archipelago. There was no consistent variation in chemical signature at the largest scale, among regions in the archipelago (separated by ~100 to 150 km). However, we found significant variation among islands within each region (10s of km), and among clutches within islands. In addition, we found that otolith cores of newly settled recruits often differed chemically from natal otoliths (which ultimately make up the otolith core as the fish grows). Variation at smaller spatial scales but not larger ones implies that otolith chemistry will only be usable if larvae disperse short distances in this system, and additional work is required to understand the relationship between the chemistry of natal otoliths and recruit cores. Otolith chemistry has the potential to address questions of connectivity, but our data suggest that these methods should be applied cautiously

On the oscillation of species

We describe a new class of BPS objects called magnetubes: their supersymmetry is determined by their magnetic charges, while their electric charges can oscillate freely between different species. We show how to incorporate these objects into microstate geometries and create BPS solutions in which the charge densities rotate through different U(1) species as one moves around a circle within the microstate geometry. Our solutions have the same “time-like” supersymmetry as five-dimensional, three-charge black holes but, in various parts of the solution, the supersymmetry takes the “null” form that is normally associated with magnetic charges. It is this property that enables the species oscillation of magnetubes to be compatible with supersymmetry. We give an example in which the species oscillate non-trivially around a circle within a microstate geometry, and yet the energy-momentum tensor and metric are completely independent of this circle: only the amplitude of the oscillation influences the metric

The Dwarf Nova PQ Andromedae

We report a photometric study of the WZ Sagittae-type dwarf nova PQ Andromedae. The light curve shows strong (0.05 mag full amplitude) signals with periods of 1263(1) and 634(1) s, and a likely double-humped signal with P=80.6(2) min. We interpret the first two as nonradial pulsation periods of the underlying white dwarf, and the last as the orbital period of the underlying binary. We estimate a distance of 150(50) pc from proper motions and the two standard candles available: the white dwarf and the dwarf-nova outburst. At this distance, the K magnitude implies that the secondary is probably fainter than any star on the main sequence -- indicating a mass below the Kumar limit at 0.075 M_sol. PQ And may be another "period bouncer", where evolution now drives the binary out to longer period.Comment: PDF, 13 pages, 2 figures; accepted, in press, to appear September 2005, PASP; more info at http://cba.phys.columbia.edu

Partial Dynamical SU(3) Symmetry and the Nature of the Lowest K=0 Collective Excitation in Deformed Nuclei

We discuss the implications of partial dynamical SU(3) symmetry (PDS) for the structure of the lowest K=0^{+} (K=0_2) collective excitation in deformed nuclei. We consider an interacting boson model Hamiltonian whose ground and gamma bands have good SU(3) symmetry while the K=0_2 band is mixed. It is shown that the double-phonon components in the K=0_2 wave function arise from SU(3) admixtures which, in turn, can be determined from absolute E2 rates connecting the K=0_2 and ground bands. An explicit expression is derived for these admixtures in terms of the ratio of K=0_2 and gamma bandhead energies. The SU(3) PDS predictions are compared with existing data and with broken-SU(3) calculations for ^{168}Er.Comment: 12 pages, 2 figure

Discordant transmission of bacteria and viruses from mothers to babies at birth

BACKGROUND: The earliest microbial colonizers of the human gut can have life-long consequences for their hosts. Precisely how the neonatal gut bacterial microbiome and virome are initially populated is not well understood. To better understand how the maternal gut microbiome influences acquisition of the infant gut microbiome, we studied the early life bacterial microbiomes and viromes of 28 infant twin pairs and their mothers. RESULTS: Infant bacterial and viral communities more closely resemble those of their related co-twin than unrelated infants. We found that 63% of an infant\u27s bacterial microbiome can be traced to their mother\u27s gut microbiota. In contrast, only 15% of their viral communities are acquired from their mother. Delivery route did not determine how much of the bacterial microbiome or virome was shared from mother to infant. However, bacteria-bacteriophage interactions were altered by delivery route. CONCLUSIONS: The maternal gut microbiome significantly influences infant gut microbiome acquisition. Vertical transmission of the bacterial microbiome is substantially higher compared to vertical transmission of the virome. However, the degree of similarity between the maternal and infant gut bacterial microbiome and virome did not vary by delivery route. The greater similarity of the bacterial microbiome and virome between twin pairs than unrelated twins may reflect a shared environmental exposure. Thus, differences of the inter-generation transmissibility at birth between the major kingdoms of microbes indicate that the foundation of these microbial communities are shaped by different rules. Video Abstract