1,969 research outputs found
The Distance to the Soft Gamma Repeater SGR 1627-41
We report millimeter observations of the line of sight to the recently
discovered Soft Gamma Repeater, SGR 1627-41, which has been tentatively
associated with the supernova remnant SNR G337.0-0.1 Among the eight molecular
clouds along the line of sight to SGR 1627-41, we show that SNR G337.0-0.1 is
probably interacting with one of the most massive giant molecular clouds (GMC)
in the Galaxy, at a distance of 11 kpc from the sun. Based on the high
extinction to the persistent X-ray counterpart of SGR 1627-41, we present
evidence for an association of this new SGR with the SNR G337.0-0.1; they both
appear to be located on the near side of the GMC. This is the second SGR
located near an extraordinarily massive GMC. We suggest that SGR 1627-41 is a
neutron star with a high transverse velocity (~ 1,000 \kms) escaping the young
(~ 5,000 years) supernova remnant G337.0-0.1Comment: 17 pages, including 2 figures. Accepted for publication in the
Astrophysical Journal Letter
Further evidence of response by leukaemia patients in remission to antigen(s) related to acute myelogenous leukaemia.
Fifteen patients with acute myelogenous leukaemia were studied to determine if their remission blood leucocytes could be stimulated into taking up [3H] thymidine after in vitro culture with their own cryo-preserved irradiated AML leukaemia cells. In 6/15 patients it was possible to show autologous recognition and equal recognition of their stored leukaemia cells, even when they had previously been maintained in in vitro proliferative cultures in liquid suspension and undergoing myeloid maturation for one week. After in vitro proliferative culture, 4 populations of leukaemia cells produced material in the supernatant media between 3 and 7 days capable of inducing [3H] thymidine uptake in autologous (2 pts, 5 supernatants) and allogeneic (2 pts, 2 supernatants) AML remission lymphocytes, but not in normal donor lymphocytes. The relevance of these observations to tumour-associated AML antigen is discussed
Safety and efficacy of recombinant human erythropoietin treatment of anaemia associated with multiple myeloma in haemodialysed patients
Recombinant human erythropoietin (rHuEpo) was used to treat the anaemia of four haemodialysed patients (3 males, 1 female) with advanced multiple myeloma; the type of serum M component was IgG kappa in all cases. During the 6-month period preceding rHuEpo therapy the patients received multiple blood transfusions (range 4-22 units of packed red cells per patient). After the first month of treatment haematocrit increased from 23±3 (SD) to 32±4% and during the last 3 months the maintenance dose of rHuEpo was 143±37 U/kg per week to achieve a mean haematocrit of 35±1%. After introduction of rHuEpo, blood transfusions were no longer required and the patients reported an improvement in wellbeing. No apparent worsening of multiple myeloma has been observed over the treatment period ranging from 5 to 34 months (cumulative duration of treatment 55 months). Anti-hypertensive therapy was started in one case and increased in two patients. We conclude that rHuEpo appears to be effective and safe in treating anaemia associated with multiple myeloma in patients requiring haemodialysi
Thickness-dependent thermal properties of amorphous insulating thin films measured by photoreflectance microscopy
In this work, we report on the measurement of the thermal conductivity of thin insulating films of SiO2 obtained by thermal oxidation, and Al2O3 grown by atomic layer deposition (ALD), both on Si wafers. We used photoreflectance microscopy to determine the thermal properties of the films as a function of thickness in the 2 nm to 1000 nm range. The effective thermal conductivity of the Al2O3 layer is shown to decrease with thickness down to 70% for the thinnest layers. The data were analyzed upon considering that the change in the effective thermal conductivity corresponds to an intrinsic thermal conductivity associated to an additional interfacial thermal resistance. The intrinsic conductivity and interfacial thermal resistance of SiO2 were found to be equal to 0.95 W/m·K and 5.1 Ă 10â 9 m2K/W respectively; those of Al2O3 were found to be 1.56 W/m·K and 4.3 Ă 10â 9 m2K/W
Solution analytique de l'écoulement en régime permanent dans un aquifÚre incliné à nappe libre, et comparaison de cette solution avec des solutions numériques plus complÚtes
Effective porosity and dispersion in stratified aquifers: closed-form solutions
RĂ©sumĂ©: Ce Rapport Technique prĂ©sente des solutions analytiques inĂ©dites pour la migration dâun traceur non rĂ©actif par Ă©coulement plan ou radial dans un aquifĂšre idĂ©al stratifiĂ©, dans le cas dâune distribution lognormale de la conductivitĂ© hydraulique K. Des solutions sont obtenues pour la porositĂ© effective et la dispersivitĂ© longitudinale de lâaquifĂšre homogĂšne hydrauliquement Ă©quivalent. La recherche conduisant Ă ces nouvelles solutions a Ă©tĂ© motivĂ©e par le fait que lâĂ©quation classique dâadvectionâdispersion nâexplique pas trois caractĂ©ristiques des courbes de restitution des essais in situ de traceurs non rĂ©actifs: (1) arrivĂ©e prĂ©coce, (2) effet dâĂ©chelle pour la dispersion longitudinale, et (3) courbe avec une longue queue. Les problĂšmes de traceurs sont rĂ©solus dâabord pour un nombre fini de souscouches afin de bien illustrer les rĂ©sultats clĂ©s, et ensuite pour une distribution lognormale de K. Pour une injection soutenue du traceur, la nouvelle Ă©quation de la courbe de restitution ressemble Ă lâĂ©quation dâadvectionâdispersion dâun aquifĂšre homogĂšne, mais avec une arrivĂ©e prĂ©coce et plus de distorsion. Des distributions, normale et lognormale, de K donnent des courbes de restitution similaires seulement dans le cas dâune faible variance. Une nouvelle Ă©quation est obtenue pour la dispersivitĂ© longitudinale : elle explique les rĂ©sultats de terrain collectĂ©s par divers auteurs, leur variation avec la distance ainsi quâavec la variance de ln (K). Pour une injection temporaire de traceur, la courbe de restitution thĂ©orique, obtenue pour une distribution lognormale de K, prĂ©sente elle aussi une arrivĂ©e prĂ©coce, une distorsion et une longue queue, qui sont les trois caractĂ©ristiques des essais de traceurs in situ. ---------- Abstract: This Technical Report provides original closed-form solutions for the migration of a non-reactive tracer due to either plane or radial seepage in an ideally stratified aquifer, in the case of a lognormal K distribution. New solutions are obtained for the effective porosity and longitudinal dispersivity of the hydraulically equivalent homogenous aquifer. The research leading to these new solutions was initiated because the classical advection-dispersion equation does not explain three features of break-through curves of field non-reactive tracer tests: (1) early arrival, (2) scale-dependent longitudinal dispersion, and (3) long tail. Initially, the tracer test problems are solved for a finite number of sub-layers to illustrate the key findings, then for a lognormal distribution of the hydraulic conductivity, K. For steady tracer injection and a lognormal K distribution, the new break-through curve equation looks like the advection-diffusion equation in a homogenous aquifer, but with an earlier arrival and more distortion. The normal and lognormal K distributions yield similar break-through curves only for a case of small variance. The new equation for the longitudinal dispersivity explains field values which have been collected by various authors, their variation with distance and also with the variance of ln (K). For a tracer injection of limited duration, the predicted break-through curve for a lognormal K distribution also yields the early arrival, a BTC distortion and long tail, which are the three features of field tracer tests
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