812 research outputs found

    Photometric and spectroscopic gamma-ray observations of solar transient phenomena using long duration balloons

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    A program currently in progress to conduct extended duration spectroscopic and photometric observation of solar X-ray phenomena from balloons is described. High photometric sensitivity to weak hard X-ray bursts is attained using a 600 sq cm array of phoswich scintillators. High spectral resolution for stronger bursts is available from an array of planar germanium detectors. These instruments are carried in a novel balloon gondola dssigned for the 15 to 20 day float durations available through using conventional zero pressure balloons in the radiation controlled (RACOON) mode

    Communicating risk from the frontline: projecting community voices into disaster risk management policies across scales, in: Urban Ark Briefing No 19. October 2018

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    Research carried out in Dar es Salaam, Tanzania on cross-scalar risk communication and disaster risk governance reveals that, while there is considerable potential for communities to measure and communicate risk and to prioritise actions, there is little scope for them to influence disaster risk governance at this point in time. This is partly because, although disaster risk management (DRM) is devolved in Tanzania, it has not gone far enough to give adequate powers and financing to the lowest level of government at the sub-wards, which are at the frontline of managing the biggest everyday risks that people face. The effective communication of risks upwards from communities to governments, and of DRM policies and opportunities downwards to communities and across sectors is crucial to overcome these gaps. When communication is participatory and collaborative, there is scope for local city actors to reflect on the need for action to be joined across governance scales, and to ensure communication plays a key role at and between all levels

    Antiviral activity of 2,3-Dihydro-1H-imidazo[1,2-b]pyrazole in herpes simplex virus type 1-infected mammalian cells

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    2,3-Dihydro-1H-imidazo[1,2-b]pyrazole (IMPY), a known inhibitor of DNA synthesis, has been shown to be a useful drug for the synchronization of mammalian cells in culture. Recent studies in our laboratory indicate that IMPY may possess significant antiviral activity against herpes simplex virus (HSV) type 1. IMPY. at a concentration of 80 [mu]g/ml or 0.73 mM, reduced syncytia formation approximately 80 per cent. A 50 per cent inhibitory dose was calculated for each drug in order to compare potency in syncytia reduction of IMPY with that of arabinosyladenine (ara-A) and arabinosyl-hypoxanthine (ara-H). Our results indicated that the antiviral potencies of the three drugs were ranked in the order ara-A > ara-H > IMPY, the 50 per cent inhibitory doses being 22, 195 and 309 [mu]M respectively. Utilizing the microplate procedure of Sidwell and Huffman [Appl. Microbiol. 22, 797 (1971)], inhibition of viral cytopathic effect was rated against drug cytotoxicity and a virus rating (VR) established. A virus rating of 0.68 was calculated for IMPY. In comparison, VR values of 0.84 and 0.66 were obtained for ara-A and ara-H respectively. In contrast to the syncytia reduction studies, IMPY appeared to possess antiviral activity equivalent to that of ara-H according to the criteria of the virus rating assay. A technique was developed for evaluating the degree of selectivity ([deg]S) of a drug with respect to its differential effect on viral and cellular DNA synthesis. IMPY was found to possess a negative selectivity at all concentrations studied, reflecting the fact that it inhibited cellular DNA synthesis more than viral DNA synthesis. In contrast, ara-A and ara-H both expressed positive degrees of selectivity in that they inhibited viral DNA synthesis more extensively than cellular DNA synthesis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/21651/1/0000035.pd

    Advanced techniques for high resolution spectroscopic observations of cosmic gamma-ray sources

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    An advanced gamma-ray spectrometer that is currently in development is described. It will obtain a sensitivity of 0.0001 ph/sq cm./sec in a 6 hour balloon observation and uses innovative techniques for background reduction and source imaging

    Global tidal impacts of large-scale ice-sheet collapses

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    Tide model output for "Wilmes et al., (2017), Global tidal impacts of large-scale ice-sheet collapses, JGR Oceans" together with the Matlab files needed to read the model binary files Please refer to the publications for details on the run setup. h0.* contains elevation output; M2 elevations can be read in Matlab using [h,th_lim,ph_lim] = h_in(filename,1); where h is tidal elevation (abs(h) gives amplitudes and angle(h) gives phase), th_lim gives latitude limits in degs N and ph_lim longitude limits in degs E u0.* contains tidal transport output; M2 transports can be read in Matlab using [u,v,th_lim,ph_lim] = u_in(filename,1); where u and v are transports in x and y direction (real(u)/hz gives tidal current strength) grid* contains the bathymetry; can be read in Matlab using [ll_lims,hz,mz,iob] = grd_in(filename); where ll_lims gives lon and lat limits, hz is water depth, mz is the land-sea mask (0 is land, 1 is water), and iob are open boundary nodes *.it_m2_k1_00.0kyrBP_ish_no0.1sal_191322_sal4 - CTRL; bathymetry: grid_etssib_1_8_paleo_glob_ice_shelves *.it_m2_k1_00.0kyrBP_ish_5mSLR_vw_no0.1sal_191333_sal4 - 5m SLR; bathymetry: grid_etssib_1_8_paleo_glob_ice_shelves_5mSLR_vw *.it_m2_k1_00.0kyrBP_ish_7mSLR_vw_no0.1sal_191336_sal4 - 7m SLR; bathymetry: grid_etssib_1_8_paleo_glob_ice_shelves_7mSLR_vw *.it_m2_k1_1_8th_00.0kyrBP_12mSLR_vw_7048752_sal4 - 12m SLR; bathymetry: grid_etssib_1_8_paleo_glob_ice_shelves_12mSLR_vw *.it_m2_k1_00.0kyrBP_no_wais_fp_5mSLR_vw_no0.1sal_191326_sal4 - No WAIS; bathymetry: grid_etssib_1_8_glob_no_wais_SLR_fingerprint_5m_EEV_vw *.it_m2_k1_00.0kyrBP_no_gris_fp_7mSLR_vw_no0.1sal_191331_sal4 - No GIS; bathymetry: grid_etssib_1_8_glob_no_gris_SLR_fingerprint_7m_EEV_vw *.it_m2_00.0kyrBP_no_wais_gis_fp_vw_375526_sal4 - No WAIS & No GIS; bathymetry: grid_etssib_1_8_glob_no_wais_gris_SLR_fingerprint_12m_EEV_v

    Cyclic AMP activates B-Raf and ERK in cyst epithelial cells from autosomal-dominant polycystic kidneys

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    Cyclic AMP activates B-Raf and ERK in cyst epithelial cells from autosomal-dominant polycystic kidneys.BackgroundThe proliferation of mural epithelial cells is a major cause of progressive cyst enlargement in autosomal-dominant polycystic kidney disease (ADPKD). Adenosine 3′, 5′ cyclic monophosphate (cAMP) stimulates the proliferation of cells from ADPKD cysts, but not cells from normal human kidney cortex (HKC), through the activation of protein kinase A (PKA), mitogen-activated protein kinase kinase (MEK), and extracellular signal-regulated kinase (ERK/MAPK). In the current study, we examined the signaling pathway between PKA and MEK in ADPKD and HKC cells.MethodsPrimary cultures of human ADPKD and HKC cells were prepared from nephrectomy specimens. We determined the effects of cAMP and epidermal growth factor (EGF) on the activation of ERK, B-Raf and Raf-1 in ADPKD and HKC cells by immune kinase assay and Western blot.Results8-Br-cAMP increased phosphorylated ERK (2.7- ± 0.6-fold, N = 7), and B-Raf kinase activity (3.6- ± 1.1-fold, N = 5) in cells from ADPKD kidneys; levels of phosphorylated Raf-1 were not changed. Inhibition of PKA by H89 strikingly decreased cAMP-stimulated phosphorylation of ERK and B-Raf, and MAPK inhibition by PD98059 blocked the effect of the nucleotide to activate ERK. By contrast, in HKC cells 8-Br-cAMP did not activate B-Raf and ERK. EGF stimulated the phosphorylation of ERK and Raf-1 in both ADPKD and HKC cells, but had no effect on B-Raf. 8-Br-cAMP and EGF conjointly increased ERK activation above that of either agonist alone in ADPKD cells, and this combined effect was abolished by PD98059, indicating that ERK was activated by EGF- and cAMP-responsive cascades that converge at MAPK.ConclusioncAMP activates ERK and increases proliferation of ADPKD epithelial cells, but not cells from normal human kidney cortex, through the sequential phosphorylation of PKA, B-Raf and MAPK in a pathway separate from, but complementary to, the classical receptor tyrosine kinase cascade. Consequently, cAMP and EGF have great potential to accelerate the progressive enlargement of renal cysts

    The bass and topological stable ranks of the Bohl algebra are infinite

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    The Bohl algebra B is the ring of linear combinations of functions t k e λt on the real line, where k is any nonnegative integer, and λ is any complex number, with pointwise operations. We show that the Bass stable rank and the topological stable rank of B (where we use the topology of uniform convergence) are infinite

    Culture shock of international students in Canada

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    vii, 85, 3 leaves ; 29 cm. --Although the immigrant's orientation to the Canadian way oflife forms a part of ESL classes, we still tend to think and speak separately of learning a second language and learning a new culture. Moreover, while acquisition ofESL is addressed by linguists and psychologists, very little research has occurred to date on the process of immigrant's acquisition of a new culture. And yet, it is held by many ESL teachers that the difficulties of 'learning the culture' upstage even the difficulties of learning English as a Second Language. (Disman, 1982, p. 71) As the number of international students increases in Canada and the number of English as a Second Language (ESL) students continues to grow in both private and public institutions, a demand for culture shock understanding is necessary by both teachers and educational institutions that deal with international students. "If language shock and cultural shock are not overcome and if the learner does not have sufficient and appropriate motivation and ego-permeability, then he will not fully acculturate and hence will not acquire the second language fully" (Schumann, 1981,p. 34). This study examines international students' experiences in one Canadian university. The foci of the study are to determine what factors contribute to culture shock and to explain the ways in which students deal with culture shock. The study also identifies international students' perceptions of how they feel teachers and educational institutions can improve in order to better facilitate the international students' induction into the new cultural milieu. The participants for this study were chosen through a screening survey from an "advanced" group of students at a university in Western Canada. From a group of 24 students, six were chosen to participate in a focus group interview. Each of the participants selected has been identified as having experienced some degree of culture shock

    Multiple Current States of Two Phase-Coupled Superconducting Rings

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    The states of two phase-coupled superconducting rings have been investigated. Multiple current states have been revealed in the dependence of the critical current on the magnetic field. The performed calculations of the critical currents and energy states in a magnetic field have made it possible to interpret the experiment as the measurement of energy states into which the system comes with different probabilities because of the equilibrium and non-equilibrium noises upon the transition from the resistive state to the superconducting state during the measurement of the critical currentComment: 5 pages, 5 figure

    Conceptualizing community resilience to natural hazards - the emBRACE framework

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    Abstract. The level of community is considered to be vital for building disaster resilience. Yet, community resilience as a scientific concept often remains vaguely defined and lacks the guiding characteristics necessary for analysing and enhancing resilience on the ground. The emBRACE framework of community resilience presented in this paper provides a heuristic analytical tool for understanding, explaining and measuring community resilience to natural hazards. It was developed in an iterative process building on existing scholarly debates, on empirical case study work in five countries and on participatory consultation with community stakeholders, where the framework was applied and ground-tested in different contexts and for different hazard types. The framework conceptualizes resilience across three core domains: resources and capacities; actions; and learning. These three domains are conceptualized as intrinsically conjoined within a whole. Community resilience is influenced by these integral elements as well as by extra-community forces, comprising disaster risk governance and thus laws, policies and responsibilities on the one hand and on the other, the general societal context, natural and human-made disturbances and system change over time. The framework is a graphically rendered heuristic, which through application can assist in guiding the assessment of community resilience in a systematic way and identifying key drivers and barriers of resilience that affect any particular hazard-exposed community
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