We investigate the effect of dark energy on the density profiles of dark matter haloes with a suite of cosmological N-body simulations and use our results to test analytic models. We consider ...constant equation of state models, and allow both w>-1 and w<-1. Using five simulations with w ranging from -1.5 to -0.5, and with more than ~1600 well-resolved haloes each, we show that the halo concentration model of Bullock et al. (2001) accurately predicts the median concentrations of haloes over the range of w, halo masses, and redshifts that we are capable of probing. We find that the Bullock et al. (2001) model works best when halo masses and concentrations are defined relative to an outer radius set by a cosmology-dependent virial overdensity. For a fixed power spectrum normalization and fixed-mass haloes, larger values of w lead to higher concentrations and higher halo central densities, both because collapse occurs earlier and because haloes have higher virial densities. While precise predictions of halo densities are quite sensitive to various uncertainties, we make broad comparisons to galaxy rotation curve data. At fixed power spectrum normalization (fixed sigma_8), w>-1 quintessence models seem to exacerbate the central density problem relative to the standard w=-1 model. Meanwhile w<-1 models help to reduce the apparent discrepancy. We confirm that the Jenkins et al. (2001) halo mass function provides an excellent approximation to the abundance of haloes in our simulations and extend its region of validity to include models with w<-1.
A new Monte-Carlo radiative-transfer code, Sunrise, is used in conjunction with hydrodynamic simulations of major galaxy mergers to calculate the effects of dust in such systems. The simulations are ...in good agreement with observations of dust absorption in starburst galaxies, and the dust has a profound effect on their appearance. The dust attenuation increases with luminosity such that at peak luminosities ~90% of the bolometric luminosity is absorbed by dust. In general, the detailed appearance of the merging event depends on the stage of the merger and the geometry of the encounter. The fraction of bolometric energy absorbed by the dust, however, is a robust quantity that can be predicted from the intrinsic properties bolometric luminosity, baryonic mass, star-formation rate, and metallicity of the system. This paper presents fitting formulae, valid over a wide range of masses and metallicities, from which the absorbed fraction of luminosity (and consequently also the infrared dust luminosity) can be predicted. The attenuation of the luminosity at specific wavelengths can also be predicted, albeit with a larger scatter due to the variation with viewing angle. These formulae for dust attenuation appear to be valid for both isolated and interacting galaxies, are consistent with earlier studies, and would be suitable for inclusion in theoretical models, e.g. semi-analytic models of galaxy formation.
We present a series of four simulations of Cold Dark Matter (CDM) and Cold + Hot Dark Matter (CHDM) cosmologies. We discuss the power spectrum and correlation functions in real and redshift space, ...with comparisons to the CfA2 and IRAS redshift data, the pairwise velocity of galaxies, and the distribution of hot and cold particles in CHDM simulations. We confirm that CHDM with cold/hot/baryon density ratios \(\Omega_c/\Omega_\nu/\Omega_b= 0.6/0.3/0.1\) is a good fit to a wide variety of present-epoch data, much better than CDM. In particular, with reasonable assumptions about identification of galaxies and biasing, we find that the power spectrum agrees rather well with both the CfA2 and IRAS power specta in both the nonlinear and linear regimes. New CHDM models (e.g., with \(\Omega_\nu=0.2\) or with two massive neutrinos) predict a significantly larger rate of formation of galaxies at high redshift, which may be needed to explain some observational data. At the same time, the difference between the variants is rather small at \(z=0\). The results presented in this paper are interesting for two purposes: (i) For a comparison with other classes of models (like CDM and \(\Lambda\)CDM) at \(z=0\).(ii) As a reference point for comparison between different variants of the CHDM model.
Retrograde venous catheterization in a hypercalcitonemic patient with adenocarcinoma of the lung demonstrated that the thyroid gland was secreting a very large amount of hormone (14-fold higher than ...the peripheral level), while the venous drainage from the tumor deposits was similar in concentration to that of the periphery. Conceivably, the calcitonin is being elaborated in response to metastatic and humoral bone resorption or both. Radiotherapy resulted in a decrease in the calcitonin level. Further studies are needed to determine the diagnostic or prognostic implications of serum calcitonin in bronchogenic cancer.
Summary
Assays for inhibition of fixation of gpC′ were described. The inhibitory activity of human sera was found to vary, but inhibitory activity was significantly elevated in sera of individuals ...having rheumatoid arthritis.
Fractionation of a number of sera of healthy donors by DEAE cellulose chromatography revealed two inhibitors of CF. In addition to these substances, a third compound occurred in the sera of individuals with rheumatoid arthritis. The compound was purified 400-fold and was shown to be a γ-macroglobulin and was distinct from RF.
Replacement resorption may follow the replantation of an avulsed tooth. Currently there is no effective treatment for replacement resorption. The purpose of this study was to investigate the effect ...of bisphosphonates and gallium nitrate, which have been shown to reduce bone resorption, on cells which resorb dentin. Osteoclast-like cells were obtained by culturing cells from prenatal chick tibeas. These cells were seeded onto slices of human dentin which had been soaked in either saline (control), or solutions of 10(-5) M 1-hydroxyethylidene-1, 1-bisphosphonic acid (EHBP), 10(-6) M dichloromethylene bisphosphonic acid (Cl2MBP), or 10(-6) M gallium nitrate. Resorption was measured by counting the number of resorptive lacunae produced by the cells. Results indicated that the experimental groups did not differ significantly from each other, but each exhibited significantly reduced resorption compared with saline controls (p < 0.01). These results suggested that the experimental treatment reduced dentinal resorption by the osteoclast-like cells, and that these agents might be useful to prevent or at least postpone replacement resorption in avulsed teeth.
Ectopic production of calcitonin Silva, O L; Becker, K L; Primack, A ...
The Lancet (British edition),
1973-Aug-11, Letnik:
2, Številka:
7824
Journal Article
Society Business Delcourt, Hazel R.; Levin, Simon A.; Pitelka, Louis F. ...
Bulletin of the Ecological Society of America,
12/1991, Letnik:
72, Številka:
4
Journal Article
