47 research outputs found
A Pinhole Camera for Radiation Research in Dentistry
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68035/2/10.1177_00220345620410013201.pd
Supergravity Inflation on the Brane
We study N=1 Supergravity inflation in the context of the braneworld
scenario. Particular attention is paid to the problem of the onset of inflation
at sub-Planckian field values and the ensued inflationary observables. We find
that the so-called -problem encountered in supergravity inspired
inflationary models can be solved in the context of the braneworld scenario,
for some range of the parameters involved. Furthermore, we obtain an upper
bound on the scale of the fifth dimension, M_5 \lsim 10^{-3} M_P, in case the
inflationary potential is quadratic in the inflaton field, . If the
inflationary potential is cubic in , consistency with observational data
requires that .Comment: 6 pages, 1 figure, to appear in Phys. Rev.
Leptogenesis through direct inflaton decay to light particles
We present a scenario of nonthermal leptogenesis following supersymmetric
hybrid inflation, in the case where inflaton decay to both heavy right handed
neutrino and SU(2)_L triplet superfields is kinematically disallowed. Lepton
asymmetry is generated through the decay of the inflaton into light particles
by the interference of one-loop diagrams with right handed neutrino and SU(2)_L
triplet exchange respectively. We require superpotential couplings explicitly
violating a U(1) R-symmetry and R-parity. However, the broken R-parity need not
have currently observable low-energy signatures. Also, the lightest sparticle
can be stable. Some R-parity violating slepton decays may, though, be
detectable in the future colliders. We take into account the constraints from
neutrino masses and mixing and the preservation of the primordial lepton
asymmetry.Comment: 11 pages including 3 figures, uses Revtex, minor corrections,
references adde
Fine-Tuning Solution for Hybrid Inflation in Dissipative Chaotic Dynamics
We study the presence of chaotic behavior in phase space in the
pre-inflationary stage of hybrid inflation models. This is closely related to
the problem of initial conditions associated to these inflationary type of
models. We then show how an expected dissipative dynamics of fields just before
the onset of inflation can solve or ease considerably the problem of initial
conditions, driving naturally the system towards inflation. The chaotic
behavior of the corresponding dynamical system is studied by the computation of
the fractal dimension of the boundary, in phase space, separating inflationary
from non-inflationary trajectories. The fractal dimension for this boundary is
determined as a function of the dissipation coefficients appearing in the
effective equations of motion for the fields.Comment: 10 pages, 4 eps figures (uses epsf), Revtex. Replaced with version to
match one in press Physical Review
How generic is cosmic string formation in SUSY GUTs
We study cosmic string formation within supersymmetric grand unified
theories. We consider gauge groups having a rank between 4 and 8. We examine
all possible spontaneous symmetry breaking patterns from the GUT down to the
standard model gauge group. Assuming standard hybrid inflation, we select all
the models which can solve the GUT monopole problem, lead to baryogenesis after
inflation and are consistent with proton lifetime measurements. We conclude
that in all acceptable spontaneous symmetry breaking schemes, cosmic string
formation is unavoidable. The strings which form at the end of inflation have a
mass which is proportional to the inflationary scale. Sometimes, a second
network of strings form at a lower scale. Models based on gauge groups which
have rank greater than 6 can lead to more than one inflationary era; they all
end by cosmic string formation.Comment: 31 pages, Latex, submitted to PR
Global surveillance of cancer survival 1995-2009: analysis of individual data for 25,676,887 patients from 279 population-based registries in 67 countries (CONCORD-2)
BACKGROUND:
Worldwide data for cancer survival are scarce. We aimed to initiate worldwide surveillance of cancer survival by central analysis of population-based registry data, as a metric of the effectiveness of health systems, and to inform global policy on cancer control.
METHODS:
Individual tumour records were submitted by 279 population-based cancer registries in 67 countries for 25·7 million adults (age 15-99 years) and 75,000 children (age 0-14 years) diagnosed with cancer during 1995-2009 and followed up to Dec 31, 2009, or later. We looked at cancers of the stomach, colon, rectum, liver, lung, breast (women), cervix, ovary, and prostate in adults, and adult and childhood leukaemia. Standardised quality control procedures were applied; errors were corrected by the registry concerned. We estimated 5-year net survival, adjusted for background mortality in every country or region by age (single year), sex, and calendar year, and by race or ethnic origin in some countries. Estimates were age-standardised with the International Cancer Survival Standard weights.
FINDINGS:
5-year survival from colon, rectal, and breast cancers has increased steadily in most developed countries. For patients diagnosed during 2005-09, survival for colon and rectal cancer reached 60% or more in 22 countries around the world; for breast cancer, 5-year survival rose to 85% or higher in 17 countries worldwide. Liver and lung cancer remain lethal in all nations: for both cancers, 5-year survival is below 20% everywhere in Europe, in the range 15-19% in North America, and as low as 7-9% in Mongolia and Thailand. Striking rises in 5-year survival from prostate cancer have occurred in many countries: survival rose by 10-20% between 1995-99 and 2005-09 in 22 countries in South America, Asia, and Europe, but survival still varies widely around the world, from less than 60% in Bulgaria and Thailand to 95% or more in Brazil, Puerto Rico, and the USA. For cervical cancer, national estimates of 5-year survival range from less than 50% to more than 70%; regional variations are much wider, and improvements between 1995-99 and 2005-09 have generally been slight. For women diagnosed with ovarian cancer in 2005-09, 5-year survival was 40% or higher only in Ecuador, the USA, and 17 countries in Asia and Europe. 5-year survival for stomach cancer in 2005-09 was high (54-58%) in Japan and South Korea, compared with less than 40% in other countries. By contrast, 5-year survival from adult leukaemia in Japan and South Korea (18-23%) is lower than in most other countries. 5-year survival from childhood acute lymphoblastic leukaemia is less than 60% in several countries, but as high as 90% in Canada and four European countries, which suggests major deficiencies in the management of a largely curable disease.
INTERPRETATION:
International comparison of survival trends reveals very wide differences that are likely to be attributable to differences in access to early diagnosis and optimum treatment. Continuous worldwide surveillance of cancer survival should become an indispensable source of information for cancer patients and researchers and a stimulus for politicians to improve health policy and health-care systems