Investigation of a liquid-fed water resistojet plume

Measurements of mass flux and flow angle were taken throughout the forward flow region of the exhaust of a liquid-fed water resistojet using a quartz crystal microbalance (QCM). The resistojet operated at a mass flow rate of 0.1 g/s with a power input of 330 Watts. Measured values were compared to theoretical predictions obtained by employing a source flow approximation. Excellent agreement between predicted and measured mass flux values was attained; however, this agreement was highly dependent on knowledge of nozzle flow conditions. Measurements of the temperature at which the exhaust condensed on the QCM were obtained as a function of incident mass flux

Speckle Interferometry of Metal-Poor Stars in the Solar Neighborhood. I

We report the results of speckle-interferometric observations of 109 high proper-motion metal-poor stars made with the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences. We resolve eight objects -- G102-20, G191-55, BD+19$^\circ$~1185A, G89-14, G87-45, G87-47, G111-38, and G114-25 -- into individual components and we are the first to astrometrically resolve seven of these stars. New resolved systems included two triple (G111-38, G87-47) and one quadruple (G89-14) star. The ratio of single-to-binary-to-triple-to-quadruple systems among the stars of our sample is equal to 71:28:6:1.Comment: 8 pages, 4 figures, accepted to Astrophysical Bulleti

Anderson Localization of Polar Eigenmodes in Random Planar Composites

Anderson localization of classical waves in disordered media is a fundamental physical phenomenon that has attracted attention in the past three decades. More recently, localization of polar excitations in nanostructured metal-dielectric films (also known as random planar composite) has been subject of intense studies. Potential applications of planar composites include local near-field microscopy and spectroscopy. A number of previous studies have relied on the quasistatic approximation and a direct analogy with localization of electrons in disordered solids. Here I consider the localization problem without the quasistatic approximation. I show that localization of polar excitations is characterized by algebraic rather than by exponential spatial confinement. This result is also valid in two and three dimensions. I also show that the previously used localization criterion based on the gyration radius of eigenmodes is inconsistent with both exponential and algebraic localization. An alternative criterion based on the dipole participation number is proposed. Numerical demonstration of a localization-delocalization transition is given. Finally, it is shown that, contrary to the previous belief, localized modes can be effectively coupled to running waves.Comment: 22 pages, 7 figures. Paper was revised and a more precise definition of the participation number given, data for figures recalculated accordingly. Accepted to J. Phys.: Cond. Mat

Hypotaurine and thiotaurine as indicators of sulfide exposure in bivalves and vestimentiferans from hydrothermal vents and cold seeps

Author Posting. © Blackwell, 2007. This is the author's version of the work. It is posted here by permission of Blackwell for personal use, not for redistribution. The definitive version was published in Marine Ecology 28 (2007): 208-218, doi:10.1111/j.1439-0485.2006.00113.x.Vesicomyid clams, vestimentiferans, and some bathymodiolin mussels from hydrothermal vents and cold seeps possess thiotrophic endosymbionts, high levels of hypotaurine and, in tissues with symbionts, thiotaurine. The latter, a product of hypotaurine and sulfide, may store and/or transport sulfide non-toxically, and the ratio to hypotaurine plus thiotaurine (Th/[H+Th]) may reflect an animal's sulfide exposure. To test this, we analyzed seep and vent animals with in situ sulfide measurements. Calyptogena kilmeri clams occur at high-sulfide seeps in Monterey Canyon, while C. (Vesicomya) pacifica clams occur at seeps with lower levels but take up and metabolize sulfide more effectively. From one seep where they co-occur, both had gill thiotaurine contents at 22-25 mmol/kg wet mass, and while C. (V.) pacifica had a higher blood sulfide level, it had a lower Th/[H+Th] (0.39) than C. kilmeri (0.63). However, these same species from different seeps with lower sulfide exposures had lower ratios. Bathymodiolus thermophilus (East Pacific Rise [EPR 9°50'N]) from high- (84 μM) and a low- (7 μM) sulfide vents had gill ratios of 0.40 and 0.12, respectively. Trophosomes of Riftia pachyptila (EPR 9°50'N) from medium- (33 μM) and low- (4 μM) sulfide vents had ratios of 0.23 and 0.20, respectively (not significantly different). Ridgeia piscesae vestimentiferans (Juan de Fuca Ridge) have very different phenotypes at high- and low-sulfide sites, and their trophosomes had the greatest differences: 0.81 and 0.04 ratios from high- and low-sulfide sites, respectively. Thus Th/[H+Th] may indicate sulfide exposure levels within species, but not in interspecies comparisons, possibly due to phylogenetic and metabolic differences. Total H+Th was constant within each species (except in R. piscesae); the sum may indicate the maximum potential sulfide load that a species faces.Funding for Ridgeia piscesae collection was grant UAF01-0042 from NOAA-West Coast National Undersea Research Center to Stephen W. Schaeffer, Charles R. Fisher, and Stéphane Hourdez. Funding for GLB, RVH and PHY was the W.M. Keck Foundation (grant to Whitman College Life Sciences program) and Whitman College Perry Grant program. Funding was from Ifremer for NLB, and The David and Lucile Packard Foundation for SKG

Development of a Diagnostic Test Set to Assess Agreement in Breast Pathology: Practical Application of the Guidelines for Reporting Reliability and Agreement Studies (GRRAS)

Diagnostic test sets are a valuable research tool that contributes importantly to the validity and reliability of studies that assess agreement in breast pathology. In order to fully understand the strengths and weaknesses of any agreement and reliability study, however, the methods should be fully reported. In this paper we provide a step-by-step description of the methods used to create four complex test sets for a study of diagnostic agreement among pathologists interpreting breast biopsy specimens. We use the newly developed Guidelines for Reporting Reliability and Agreement Studies (GRRAS) as a basis to report these methods

Teologija na tržištu

One task intended to measure sensitivity to temporal fine structure (TFS) involves the discrimination of a harmonic complex tone from a tone in which all harmonics are shifted upwards by the same amount in hertz. Both tones are passed through a fixed bandpass filter centered on the high harmonics to reduce the availability of excitation-pattern cues and a background noise is used to mask combination tones. The role of frequency selectivity in this "TFS1" task was investigated by varying level. Experiment 1 showed that listeners performed more poorly at a high level than at a low level. Experiment 2 included intermediate levels and showed that performance deteriorated for levels above about 57 dB sound pressure level. Experiment 3 estimated the magnitude of excitation-pattern cues from the variation in forward masking of a pure tone as a function of frequency shift in the complex tones. There was negligible variation, except for the lowest level used. The results indicate that the changes in excitation level at threshold for the TFS1 task would be too small to be usable. The results are consistent with the TFS1 task being performed using TFS cues, and with frequency selectivity having an indirect effect on performance via its influence on TFS cues. (C) 2015 Acoustical Society of America

Tetraspanins in zebrafish development

Introduction: Tetraspanins represent a family of integral membrane proteins involved in cell-cell interaction, including adhesion, fusion, differentiation and proliferation. These basic functions are essential for embryonic development, yet there is little research on the role of tetraspanins in this process. The aim of my project is to pilot zebrafish as a new and sensitive model for assessing tetraspanin function in vertebrate development. Background: There are approximately 50 tetraspanin genes in zebrafish, representing orthologues of most of the 33 mammalian genes. mRNA expression analysis has shown that at least 22 of these are expressed in zebrafish embryos and thus may regulate developmental processes. CD9 is a well-characterized tetraspanin and we have shown that zebrafish CD9 orthologues are present in the posterior lateral line (pLL), a sensory system comprised of hair-cell containing neuromasts. The development of the pLL coordinates proliferation, deposition and migration simultaneously and thus requires highly regulated cell interactions. Major findings: We generated CRISPR double knockouts (dKOs) of both zebrafish CD9 paralogues. The dKOs are adult viable and fertile, in contrast to mouse CD9 KO females which are sterile. Inspection of the pLL in the CD9 KOs revealed that there is measurably slower migration of the primordium and fewer hair cells in the posterior neuromasts at 10 dpf. Furthermore we observed a reduced regenerative capacity of the dKO neuromasts, and also upregulation of CD9 paralogues during bone repair. Conclusions: Our results suggest a role for CD9 in collective cell migration and hair cell development. We will analyse the organisation and migration of the primordium in more detail as well as the development and regeneration of the neuromasts and bone. This will be aided by generating fluorescent transgenic zebrafish to visualise dynamic processes involved. This offers a unique insight into the in vivo function of tetraspanins

A common genetic target for environmental and heritable influences on aggressiveness in Drosophila

Environmental and genetic factors can modulate aggressiveness, but the biological mechanisms underlying their influence are largely unknown. Social experience with conspecifics suppresses aggressiveness in both vertebrate and invertebrate species, including Drosophila. We searched for genes whose expression levels correlate with the influence of social experience on aggressiveness in Drosophila by performing microarray analysis of head tissue from socially isolated (aggressive) vs. socially experienced (nonaggressive) male flies. Among {approx}200 differentially expressed genes, only one was also present in a gene set previously identified by profiling Drosophila strains subjected to genetic selection for differences in aggressiveness [Dierick HA, Greenspan RJ (2006) Nat Genet 38:1023–1031]. This gene, Cyp6a20, encodes a cytochrome P450. Social experience increased Cyp6a20 expression and decreased aggressiveness in a reversible manner. In Cyp6a20 mutants, aggressiveness was increased in group-housed but not socially isolated flies. These data identify a common genetic target for environmental and heritable influences on aggressiveness. Cyp6a20 is expressed in a subset of nonneuronal support cells associated with pheromone-sensing olfactory sensilla, suggesting that social experience may influence aggressiveness by regulating pheromone sensitivity

Can the Experience of Participatory Development Help Think Critically about ‘Patient and Public Involvement’ in UK Healthcare?

The expansion of spaces for ‘patient and public involvement’ (PPI) in health systems in the UK is a relatively recent phenomenon, and yet ‘participation’ as a principle for planned interventions in international development is well established as a field of practice and controversy. Development workers and scholars have passed through moments of enchantment and disenchantment with the idea that the true source of innovation, expertise and workable (and sustainable) solutions is to be found not in the professionals but in communities of experience. Making ‘local knowledge’ the basis of interventions has proved unexpectedly problematic. How could incommensurable forms of knowing, across steep gradients of power be bridged? This article describes a decade-long experiment in participatory development in a remote Adivasi (tribal) region of western India in order to suggest the relevance of this experience for the very different context of PPI in healthcare settings. In particular, it highlights some general points about knowledge practices at the interface, and the human tendency to adjust, mirror, mimic, loop and in other ways make the ‘patient-professional’ interface itself hard to navigate. The article suggests that self-reflective insight into these social processes is necessary for effective ‘engagement’ by professional and lay actors alike