1,853 research outputs found
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Book review: John Mair, Tor Clark, Neil Fowler, Raymond Snoddy and Richard Tait (eds) Anti-social media? The impact on journalism and society
Global Curriculum in Surgical Oncology
Background
The significant global variations in surgical oncology training paradigms can have a detrimental effect on tackling the rising global cancer burden. While some variations in training are essential to account for the differences in types of cancer and biology, the fundamental principles of providing care to a cancer patient remain the same. The development of a global curriculum in surgical oncology with incorporated essential standards could be very useful in building an adequately trained surgical oncology workforce, which in turn could help in tackling the rising global cancer burden.
Materials and Methods
The leaders of the Society of Surgical Oncology and European Society of Surgical Oncology convened a global curriculum committee to develop a global curriculum in surgical oncology.
Results
A global curriculum in surgical oncology was developed to incorporate the required domains considered to be essential in training a surgical oncologist. The curriculum was constructed in a modular fashion to permit flexibility to suit the needs of the different regions of the world. Similarly, recognizing the various sociocultural, financial and cultural influences across the world, the proposed curriculum is aspirational and not mandatory in intent.
Conclusions
A global curriculum was developed which may be considered as a foundational scaffolding for training surgical oncologists worldwide. It is envisioned that this initial global curriculum will provide a flexible and modular scaffolding that can be tailored by individual countries or regions to train surgical oncologists in a way that is appropriate for practice in their local environmen
Constraints on Beta Functions from Duality
We analyze the way in which duality constrains the exact beta function and
correlation length in single-coupling spin systems. A consistency condition we
propose shows very concisely the relation between self-dual points and phase
transitions, and implies that the correlation length must be duality invariant.
These ideas are then tested on the 2-d Ising model, and used towards finding
the exact beta function of the -state Potts model. Finally, a generic
procedure is given for identifying a duality symmetry in other single-coupling
models with a continuous phase transition.Comment: LaTeX, 6 page
Nonrenormalization of Flux Superpotentials in String Theory
Recent progress in understanding modulus stabilization in string theory
relies on the existence of a non-renormalization theorem for the 4D
compactifications of Type IIB supergravity which preserve N=1 supersymmetry. We
provide a simple proof of this non-renormalization theorem for a broad class of
Type IIB vacua using the known symmetries of these compactifications, thereby
putting them on a similar footing as the better-known non-renormalization
theorems of heterotic vacua without fluxes. The explicit dependence of the
tree-level flux superpotential on the dilaton field makes the proof more subtle
than in the absence of fluxes.Comment: 16 pages, no figures. Final version, to appear in JHEP. Arguments for
validity of R-symmetry made more explicit. Minor extra comments and
references adde
Data-based estimates of the ocean carbon sink variability – First results of the Surface Ocean pCO2 Mapping intercomparison (SOCOM)
Using measurements of the surface-ocean CO2 partial pressure (pCO2) and 14 different pCO2 mapping methods recently collated by the Surface Ocean pCO2 Mapping intercomparison (SOCOM) initiative, variations in regional and global sea–air CO2 fluxes are investigated. Though the available mapping methods use widely different approaches, we find relatively consistent estimates of regional pCO2 seasonality, in line with previous estimates. In terms of interannual variability (IAV), all mapping methods estimate the largest variations to occur in the eastern equatorial Pacific. Despite considerable spread in the detailed variations, mapping methods that fit the data more closely also tend to agree more closely with each other in regional averages. Encouragingly, this includes mapping methods belonging to complementary types – taking variability either directly from the pCO2 data or indirectly from driver data via regression. From a weighted ensemble average, we find an IAV amplitude of the global sea–air CO2 flux of 0.31 PgC yr−1 (standard deviation over 1992–2009), which is larger than simulated by biogeochemical process models. From a decadal perspective, the global ocean CO2 uptake is estimated to have gradually increased since about 2000, with little decadal change prior to that. The weighted mean net global ocean CO2 sink estimated by the SOCOM ensemble is −1.75 PgC yr−1 (1992–2009), consistent within uncertainties with estimates from ocean-interior carbon data or atmospheric oxygen trend
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Direct measurements of CO2 flux in the Greenland Sea
During summer 2006 eddy correlation CO2 fluxes were measured in the Greenland Sea using a novel system set-up with two shrouded LICOR-7500 detectors. One detector was used exclusively to determine, and allow the removal of, the bias on CO2 fluxes due to sensor motion. A recently published correction method for the CO2-H2O cross-correlation was applied to the data set. We show that even with shrouded sensors the data require significant correction due to this cross-correlation. This correction adjusts the average CO2 flux by an order of magnitude from -6.7 x 10⁻² mol m⁻² day⁻¹ to -0.61 x 10⁻² mol m⁻² day⁻¹, making the corrected fluxes comparable to those calculated using established parameterizations for transfer velocity
Equilibrium configurations of two charged masses in General Relativity
An asymptotically flat static solution of Einstein-Maxwell equations which
describes the field of two non-extreme Reissner - Nordstr\"om sources in
equilibrium is presented. It is expressed in terms of physical parameters of
the sources (their masses, charges and separating distance). Very simple
analytical forms were found for the solution as well as for the equilibrium
condition which guarantees the absence of any struts on the symmetry axis. This
condition shows that the equilibrium is not possible for two black holes or for
two naked singularities. However, in the case when one of the sources is a
black hole and another one is a naked singularity, the equilibrium is possible
at some distance separating the sources. It is interesting that for
appropriately chosen parameters even a Schwarzschild black hole together with a
naked singularity can be "suspended" freely in the superposition of their
fields.Comment: 4 pages; accepted for publication in Phys. Rev.
Monte Carlo Exploration of Warped Higgsless Models
We have performed a detailed Monte Carlo exploration of the parameter space
for a warped Higgsless model of electroweak symmetry breaking in 5 dimensions.
This model is based on the gauge group
in an AdS bulk with arbitrary gauge kinetic terms on both the Planck and
TeV branes. Constraints arising from precision electroweak measurements and
collider data are found to be relatively easy to satisfy. We show, however,
that the additional requirement of perturbative unitarity up to the cut-off,
TeV, in elastic scattering in the absence of dangerous
tachyons eliminates all models. If successful models of this class exist, they
must be highly fine-tuned.Comment: 26 pages, 7 figures; new fig and additional text adde
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