10,303 research outputs found
Thermomechanical Behavior of the HL-LHC 11 Tesla Nb3Sn Magnet Coil Constituents during Reaction Heat Treatment
The knowledge of the temperature induced changes of the superconductor
volume, and of the thermo-mechanical behaviour of the different coil and
tooling materials is required for predicting the coil geometry and the stress
distribution in the coil after the Nb3Sn reaction heat treatment. In the
present study we have measured the Young's and shear moduli of the HL-LHC 11 T
Nb3Sn dipole magnet coil and reaction tool constituents during in situ heat
cycles with the dynamic resonance method. The thermal expansion behaviours of
the coil components and of a free standing Nb3Sn wire were compared based on
dilation experiments.Comment: 6 pages, 12 figures, presented at MT25 conferenc
Cold gas in the inner regions of intermediate redshift clusters
Determining gas content and star formation rate has known remarkable progress
in field galaxies, but has been much less investigated in galaxies inside
clusters. We present the first CO observations of luminous infrared galaxies
(LIRGs) inside the virial radii of two intermediate redshift clusters,
CL1416+4446 (z=0.397) and CL0926+1242 (z=0.489). We detect three galaxies at
high significance (5 to 10 sigma), and provide robust estimates of their CO
luminosities, L'CO. In order to put our results into a general context, we
revisit the relation between cold and hot gas and stellar mass in nearby field
and cluster galaxies. We find evidence that at fixed LIR (or fixed stellar
mass), the frequency of high L'CO galaxies is lower in clusters than in the
field, suggesting environmental depletion of the reservoir of cold gas. The
level of star formation activity in a galaxy is primarily linked to the amount
of cold gas, rather than to the galaxy mass or the lookback time. In clusters,
just as in the field, the conversion between gas and stars seems universal. The
relation between LIR and L'CO for distant cluster galaxies extends the relation
of nearby galaxies to higher IR luminosities. Nevertheless, the intermediate
redshift galaxies fall well within the dispersion of the trend defined by local
systems. Considering that L'CO is generally derived from the CO(1-0) line and
sensitive to the vast majority of the molecular gas in the cold interstellar
medium of galaxies, but less to the part which will actually be used to form
stars, we suggest that molecular gas can be stripped before the star formation
rate is affected. Combining the sample of Geach et al. (2009, 2011) and ours,
we find evidence for a decrease in CO towards the cluster centers. This is the
first hint of an environmental impact on cold gas at intermediate redshift.Comment: Accepted for publication in Astronomy and Astrophysic
Mathematical and computational studies of equilibrium capillary free surfaces
The results of several independent studies are presented. The general question is considered of whether a wetting liquid always rises higher in a small capillary tube than in a larger one, when both are dipped vertically into an infinite reservoir. An analytical investigation is initiated to determine the qualitative behavior of the family of solutions of the equilibrium capillary free-surface equation that correspond to rotationally symmetric pendent liquid drops and the relationship of these solutions to the singular solution, which corresponds to an infinite spike of liquid extending downward to infinity. The block successive overrelaxation-Newton method and the generalized conjugate gradient method are investigated for solving the capillary equation on a uniform square mesh in a square domain, including the case for which the solution is unbounded at the corners. Capillary surfaces are calculated on the ellipse, on a circle with reentrant notches, and on other irregularly shaped domains using JASON, a general purpose program for solving nonlinear elliptic equations on a nonuniform quadrilaterial mesh. Analytical estimates for the nonexistence of solutions of the equilibrium capillary free-surface equation on the ellipse in zero gravity are evaluated
Danish Aid Policy: Theory and Empirical Evidence
This paper is a study of Danish aid policy from the early 1960s to 1995. It includes (i) a review of officially stated aims and criteria, (ii) a descriptive analysis of actual behaviour in international comparative perspective, (iii) a review of the theoretical and empirical aid allocation literature, and (iv) a series of panel data regressions to further explore how Danish bilateral aid was, in actual fact, distributed country-by-country. A theoretical model explaining how the allocation process took place is also formulated. It underpins the empirical analysis from which it transpires that a two step model is a useful way of analysing Danish aid allocations. The first step is whether to select a country or not, and the second involves the decision of how much aid to commit. The empirical analysis demonstrates that Danish aid has been guided in both steps by officially stated aims and criteria in an expected and statistically significant manner although a clear Eastern and Southern Africa bias was found. Another general result is that the relative weights of the explanatory variables have varied both from year-to-year and between sub-periods.Danish foreign aid; modelling aid allocation; panel data analysis
The Public Interest and Bell Entry into Long-Distance Under Section 271 of the Communications Act
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The effects of school climate and selected school climate variables on the outcomes of clinical supervision.
The purpose of this study was to determine the effects of school climate on the outcomes of clinical supervision. Hypotheses stated that the overall school climate and the climate variables of caring and opportunity for input enhance, enable, and predict productive clinical supervision. A search of the literature revealed critical interrelationships between both underlying assumptions and practices of clinical supervision and school climate concepts. An analysis of school climate factors as they facilitate or hinder productive clinical supervision in public schools revealed strong arguments for the need to obtain an understanding of school climate in order to implement and support clinical supervision efforts. Consistency between school climate factors and clinical supervision is a natural tendency that effects the outcomes of the supervision. This same tendency exists between all organizational suprasystems and subsystems within. In nine schools utilizing clinical supervision (including both elementary and middle school levels) teacher perceptions were surveyed. Two hundred seven teachers completed a four part questionnaire which included the following instruments: (1) general information about participants, (2) an instrument developed by the researcher to assess the quality of the clinical supervision model used in each school, (3) an instrument to assess the productivity of the clinical supervision developed by Shuma (1973) and modified and revised by the researcher, and (4) the Questionnaire Developed from Factor Analysis of the CKF Ltd. School Climate Profile. The data consisted of responses on a scale of 1 to 4, as well as responses to open-ended questions. The analysis included tests of reliability, correlation, hierarchical multiple regression, and content analysis of specific items. Findings were significant to the .01 level and strongly supportive of the hypotheses. Some of the conclusions drawn were: (1) The quality of supervision is a strong predictor of the outcomes of the supervision. (2) The quality of supervision and outcomes of supervision scales were statistically reliable instruments useful to assess clinical supervision currently in use in the public schools. (3) Each of the school climate variables proved to be useful in the prediction of clinical supervision outcomes. (4) School level did not make a difference in any of the results. (5) In this sample the principal productively practiced clinical supervision while also serving the role of evaluator. (6) In this sample clinical supervision was productive in public schools. (7) There is a complementary interrelationship between a healthy school climate and a high quality clinical supervision model. (8) School climate factors and their effects on clinical supervision are understandable and within the power of school personnel to alter. Also outlined are five methods of using climate data to effectively implement clinical supervision. It is suggested that ignoring climate factors severely decreases the likelihood of productive clinical supervision. A strong case is made for building school climate by design and planning rather than allowing it to occur by default because of the strong relationship between climate and clinical supervision (as well as other subsystems). Additional conclusions and recommendations for both the practitioner and researcher are offered. Communications with experts from over a dozen states and conjecture on applications of the study are discussed in the epilogue
The Cosmological Constant and Advanced Gravitational Wave Detectors
Interferometric gravitational wave detectors could measure the frequency
sweep of a binary inspiral [characterized by its chirp mass] to high accuracy.
The observed chirp mass is the intrinsic chirp mass of the binary source
multiplied by , where is the redshift of the source. Assuming a
non-zero cosmological constant, we compute the expected redshift distribution
of observed events for an advanced LIGO detector. We find that the redshift
distribution has a robust and sizable dependence on the cosmological constant;
the data from advanced LIGO detectors could provide an independent measurement
of the cosmological constant.Comment: 13 pages plus 5 figure, LaTeX. Revised and final version, to appear
in Phys. Rev.
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Fcgamma receptor-mediated phagocytosis in macrophages lacking the Src family tyrosine kinases Hck, Fgr, and Lyn.
Macrophage Fcgamma receptors (FcgammaRs) mediate the uptake and destruction of antibody-coated viruses, bacteria, and parasites. We examined FcgammaR signaling and phagocytic function in bone marrow-derived macrophages from mutant mice lacking the major Src family kinases expressed in these cells, Hck, Fgr, and Lyn. Many FcgammaR-induced functional responses and signaling events were diminished or delayed in these macrophages, including immunoglobulin (Ig)G-coated erythrocyte phagocytosis, respiratory burst, actin cup formation, and activation of Syk, phosphatidylinositol 3-kinase, and extracellular signal-regulated kinases 1 and 2. Significant reduction of IgG-dependent phagocytosis was not seen in hck(-)(/)-fgr(-)(/)- or lyn(-)(/)- cells, although the single mutant lyn(-)(/)- macrophages did manifest signaling defects. Thus, Src family kinases clearly have roles in two events leading to FcgammaR-mediated phagocytosis, one involving initiation of actin polymerization and the second involving activation of Syk and subsequent internalization. Since FcgammaR-mediated phagocytosis did occur at modest levels in a delayed fashion in triple mutant macrophages, these Src family kinases are not absolutely required for uptake of IgG-opsonized particles
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