144 research outputs found
African American Adults’ Experiences with the Health Care System: In Their Own Words
African Americans suffer a disproportionate burden of death and illness from a number of different chronic diseases. Inequalities in health care practices and poor patient and provider communication between African American patients and health care professionals contribute to these disparities. We describe findings from focus groups with 79 urban African Americans in which the participants discussed their interactions with the healthcare system as well as beliefs and opinions of the healthcare system and professionals. Analysis revealed five major themes: (1) historical and contextual foundations; (2) interpersonal experiences with physicians and other health care workers; (3) discrimination; (4) trust, opinions and attitudes, and (5) improving health care experiences. These findings indicate that perceptions of discrimination and racism were prevalent among African Americans in this study, and that the expectation of a negative interaction is a barrier to seeking care. Authors discuss prevention and public health implications of these findings and make recommendations for health care practitioners
GRB970228 and the class of GRBs with an initial spikelike emission: do they follow the Amati relation?
On the basis of the recent understanding of GRB050315 and GRB060218, we
return to GRB970228, the first Gamma-Ray Burst (GRB) with detected afterglow.
We proposed it as the prototype for a new class of GRBs with "an occasional
softer extended emission lasting tenths of seconds after an initial spikelike
emission". Detailed theoretical computation of the GRB970228 light curves in
selected energy bands for the prompt emission are presented and compared with
observational BeppoSAX data. From our analysis we conclude that GRB970228 and
likely the ones of the above mentioned new class of GRBs are "canonical GRBs"
have only one peculiarity: they exploded in a galactic environment, possibly
the halo, with a very low value of CBM density. Here we investigate how
GRB970228 unveils another peculiarity of this class of GRBs: they do not
fulfill the "Amati relation". We provide a theoretical explanation within the
fireshell model for the apparent absence of such correlation for the GRBs
belonging to this new class.Comment: 5 pages, 3 figures, in the Proceedings of the "4th Italian-Sino
Workshop on Relativistic Astrophysics", held in Pescara, Italy, July 20-28,
2007, C.L. Bianco, S.-S. Xue, Editor
Evidences for a double component in the emission of GRB 101023
In this work we present the results of the analysis of GRB 101023 in the fireshell scenario. Its redshift is not known, so we attempted to infer it from the Amati Relation, obtaining z = 0.9. Its light curve presents a double emission, which makes it very similar to the already studied GRB 090618. We called each part Episode 1 and Episode 2. We performed a time-resolved spectral analysis with RMFIT using different spectral models, and fitted the light curve with a numerical code integrating the fireshell equations of motion. We used Fermi GBM data to build the light curve, in particular the second NaI detector, in the range (8.5–1000 keV). We considered different hypotheses regarding which part of the light curve could be the GRB and performed the analysis of all of them. We noticed a great variation of the temperature with time in the first episode, as well as almost no variation of the progenitor radius. We found that the first emission does not match the requirements for a GRB, while the second part perfectly agrees with being a canonical GRB, with a P-GRB lasting 4 s
Discussing Cancer: Communication With African Americans
Regular screening for colorectal cancer (CRC) facilitates earlier detection, lowers mortality, and may reduce incidence through detection and removal of pre-cancerous polyps. Optimizing health professional delivery of CRC screening information and recommendations can assist in reducing CRC disparity in the African American community. This paper presents qualitative data on African Americans’ attitudes about health professional CRC communications based on the analysis of focus groups (N=79). Using a social-ecological framework, colorectal cancer and professional communication themes are examined to offer four general and nine cancer specific theoretically based and culturally appropriate strategies for improving health professional cancer communication with African Americans
Evidence for a proto-black hole and a double astrophysical component in GRB 101023
[Shortened] Context: [...] we point out a striking similarity between GRB
101023 and GRB 090618. We explore the possibility that these sources are
members of a new GRB family related to a single core-collapse. We use this
understanding of the source in order to infer the unobserved redshift of GRB
101023. [...]. Aims: In precise analogy with GRB 090618 we aim to analyze the
89s of emission of GRB 101023 to see if we are in presence of two different
episodes: the first one presenting a characteristic Black-body temperature
evolution, evolving in time with a broken power-law, and the second one
consistent with a canonical GRB. [...] Results: We confirm that the first
episode can be well fit by a Black body plus a power-law model. The temperature
changes with time following a broken power law, and the photon index of the
power-law component presents a soft to hard evolution. We estimate the radius
of this source, increasing with time with a velocity of 1.5x10^4 km/s. The
second episode appears to be a canonical GRB. By using the Amati relation and
the Atteia relation, we determine the cosmological redshift, z ~ 0.9 +- 0.084
(stat.) +- 0.2 (sys.). [...]. Particularly striking is the scaling law of the
soft X-ray component of the afterglow. Conclusions: We identify GRB 090618 and
GRB 101023 with a new family of GRBs presenting a double astrophysical
component. A first one, related to the proto-black hole, prior to the process
of gravitational collapse (episode 1) and a second one which is the canonical
GRB (episode 2) emitted during the formation of the black-hole. [...] This
analysis indicates progress towards developing a GRB distance indicator based
on the understanding of the P-GRB and the prompt radiation as well as the soft
X-Ray behavior of the late afterglow.Comment: 11 pages, 18 figures, accepted on A&A. New version fixing some typos.
This is the version actually in pres
The Amati relation in the "fireshell" model
(Shortened) CONTEXT: [...] AIMS: Motivated by the relation proposed by Amati
and collaborators, we look within the ``fireshell'' model for a relation
between the peak energy E_p of the \nu F_\nu total time-integrated spectrum of
the afterglow and the total energy of the afterglow E_{aft}, which in our model
encompasses and extends the prompt emission. METODS: [...] Within the fireshell
model [...] We can then build two sets of ``gedanken'' GRBs varying the total
energy of the electron-positron plasma E^{e^\pm}_{tot} and keeping the same
baryon loading B of GRB050315. The first set assumes for the effective CBM
density the one obtained in the fit of GRB050315. The second set assumes
instead a constant CBM density equal to the average value of the GRB050315
prompt phase. RESULTS: For the first set of ``gedanken'' GRBs we find a
relation E_p\propto (E_{aft})^a, with a = 0.45 \pm 0.01, whose slope strictly
agrees with the Amati one. Such a relation, in the limit B \to 10^{-2},
coincides with the Amati one. Instead, in the second set of ``gedanken'' GRBs
no correlation is found. CONCLUSIONS: Our analysis excludes the Proper-GRB
(P-GRB) from the prompt emission, extends all the way to the latest afterglow
phases and is independent on the assumed cosmological model, since all
``gedanken'' GRBs are at the same redshift. The Amati relation, on the other
hand, includes also the P-GRB, focuses on the prompt emission only, and is
therefore influenced by the instrumental threshold which fixes the end of the
prompt emission, and depends on the assumed cosmology. This may well explain
the intrinsic scatter observed in the Amati relation.Comment: 4 pages, 5 figures, to appear on A&A Letter
The canonical GRB scenario
The canonical GRB scenario implied by the fireshell model is briefly summarized
GRB060218 and GRBs associated with Supernovae Ib/c
We plan to fit the complete gamma- and X-ray light curves of the long
duration GRB060218, including the prompt emission, in order to clarify the
nature of the progenitors and the astrophysical scenario of the class of GRBs
associated to SNe Ib/c. The initial total energy of the electron-positron
plasma E_{e^\pm}^{tot}=2.32\times 10^{50} erg has a particularly low value
similarly to the other GRBs associated with SNe. For the first time we observe
a baryon loading B=10^{-2} which coincides with the upper limit for the
dynamical stability of the fireshell. The effective CircumBurst Medium (CBM)
density shows a radial dependence n_{cbm} \propto r^{-\alpha} with
1.0<\alpha<1.7 and monotonically decreases from 1 to 10^{-6} particles/cm^3.
Such a behavior is interpreted as due to a fragmentation in the fireshell.
Analogies with the fragmented density and filling factor characterizing Novae
are outlined. The fit presented is particularly significant in view of the
complete data set available for GRB060218 and of the fact that it fulfills the
Amati relation. We fit GRB060218, usually considered as an X-Ray Flash (XRF),
as a "canonical GRB" within our theoretical model. The smallest possible black
hole, formed by the gravitational collapse of a neutron star in a binary
system, is consistent with the especially low energetics of the class of GRBs
associated with SNe Ib/c. We give the first evidence for a fragmentation in the
fireshell. Such a fragmentation is crucial in explaining both the unusually
large T_{90} and the consequently inferred abnormal low value of the CBM
effective density.Comment: 4 pages, 3 figures, to appear in A&A Letter
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