1,161 research outputs found
Renormalization of NN-Scattering with One Pion Exchange and Boundary Conditions
A non perturbative renormalization scheme for Nucleon-Nucleon interaction
based on boundary conditions at short distances is presented and applied to the
One Pion Exchange Potential. It is free of off-shell ambiguities and
ultraviolet divergences, provides finite results at any step of the calculation
and allows to remove the short distance cut-off in a suitable way. Low energy
constants and their non-perturbative evolution can directly be obtained from
experimental threshold parameters in a completely unique and model independent
way when the long range explicit pion effects are eliminated. This allows to
compute scattering phase shifts which are, by construction consistent with the
effective range expansion to a given order in the C.M. momentum . In the
singlet and triplet channels ultraviolet fixed points
and limit cycles are obtained respectively for the threshold parameters. Data
are described satisfactorily up to CM momenta of about .Comment: 22 pages, 10 figures, revte
Deuteron form factors in chiral effective theory: regulator-independent results and the role of two-pion exchange
We evaluate the deuteron charge, quadrupole, and magnetic form factors using
wave functions obtained from chiral effective theory (ET) when the
potential includes one-pion exchange, chiral two-pion exchange, and genuine
contact interactions. We study the manner in which the results for form factors
behave as the regulator is removed from the ET calculation, and compare
co-ordinate- and momentum-space approaches. We show that, for both the LO and
NNLO chiral potential, results obtained by imposing boundary conditions in
co-ordinate space at are equivalent to the limit of
momentum-space calculations. The regulator-independent predictions for deuteron
form factors that result from taking the limit using the
LO ET potential are in reasonable agreement with data up to momentum
transfers of order 600 MeV, provided that phenomenological information for
nucleon structure is employed. In this range the use of the NNLO ET
potential results in only small changes to the LO predictions, and it improves
the description of the zero of the charge form factor
ÂżEstĂĄn las bibliotecas pĂșblicas mejorando la calidad de la educaciĂłn? Cuando la provisiĂłn de bienes pĂșblicos no es suficiente
We analyze the relation between public, education-related infrastructure and the quality of education in schools using a case-study of the construction and implementation of two large public libraries in low-income areas in BogotĂĄ, Colombia. We assess the impact of these libraries on quality of education by comparing results in national test scores (Saber 11°) for schools close and far from these libraries before (2000-2002) and after (2003-2008) the librariesâ opening. We find non-statistically different from zero differences that could be attributed to the librariesâ implementation. We also introduce Oaxaca-Blinder decomposition on Difference-in-Differences (DiD) estimates in order to assess if variation of traditional determinants of test scores for mathematics, verbal and science explain the result estimates. These results are robust to alternative specifications of DiD, a synthetic control approach and an alternative measure of distance
Nucleon-Nucleon interaction, charge symmetry breaking and renormalization
We study the interplay between charge symmetry breaking and renormalization
in the NN system for s-waves. We find a set of universality relations which
disentangle explicitly the known long distance dynamics from low energy
parameters and extend them to the Coulomb case. We analyze within such an
approach the One-Boson-Exchange potential and the theoretical conditions which
allow to relate the proton-neutron, proton-proton and neutron-neutron
scattering observables without the introduction of extra new parameters and
providing good phenomenological success.Comment: 15 pages, 6 figure
Deconstructing 1S0 nucleon-nucleon scattering
A distorted-wave method is used to analyse nucleon-nucleon scattering in the
1S0 channel. Effects of one-pion exchange are removed from the empirical phase
shift to all orders by using a modified effective-range expansion. Two-pion
exchange is then subtracted in the distorted-wave Born approximation, with
matrix elements taken between scattering waves for the one-pion exchange
potential. The residual short-range interaction shows a very rapid energy
dependence for kinetic energies above about 100 MeV, suggesting that the
breakdown scale of the corresponding effective theory is only 270MeV. This may
signal the need to include the Delta resonance as an explicit degree of freedom
in order to describe scattering at these energies. An alternative strategy of
keeping the cutoff finite to reduce large, but finite, contributions from the
long-range forces is also discussed.Comment: 10 pages, 2 figures (introduction revised, references added; version
to appear in EPJA
Causality bounds for neutron-proton scattering
We consider the constraints of causality and unitarity for the low-energy
interactions of protons and neutrons. We derive a general theorem that
non-vanishing partial-wave mixing cannot be reproduced with zero-range
interactions without violating causality or unitarity. We define and calculate
interaction length scales which we call the causal range and the Cauchy-Schwarz
range for all spin channels up to J = 3. For some channels we find that these
length scales are as large as 5 fm. We investigate the origin of these large
lengths and discuss their significance for the choice of momentum cutoff scales
in effective field theory and universality in many-body Fermi systems.Comment: 36 pages, 10 figures, 7 tables, version to appear in Eur. Phys. J.
Management of Patients with Advanced Prostate Cancer. Part I: Intermediate-/High-risk and Locally Advanced Disease, Biochemical Relapse, and Side Effects of Hormonal Treatment: Report of the Advanced Prostate Cancer Consensus Conference 2022
Hormonal treatment; Prostate cancer; Side effectsTratamiento hormonal; CĂĄncer de prĂłstata; Efectos secundariosTractament hormonal; CĂ ncer de prĂČstata; Efectes secundarisBackground
Innovations in imaging and molecular characterisation and the evolution of new therapies have improved outcomes in advanced prostate cancer. Nonetheless, we continue to lack high-level evidence on a variety of clinical topics that greatly impact daily practice. To supplement evidence-based guidelines, the 2022 Advanced Prostate Cancer Consensus Conference (APCCC 2022) surveyed experts about key dilemmas in clinical management.
Objective
To present consensus voting results for select questions from APCCC 2022.
Design, setting, and participants
Before the conference, a panel of 117 international prostate cancer experts used a modified Delphi process to develop 198 multiple-choice consensus questions on (1) intermediate- and high-risk and locally advanced prostate cancer, (2) biochemical recurrence after local treatment, (3) side effects from hormonal therapies, (4) metastatic hormone-sensitive prostate cancer, (5) nonmetastatic castration-resistant prostate cancer, (6) metastatic castration-resistant prostate cancer, and (7) oligometastatic and oligoprogressive prostate cancer. Before the conference, these questions were administered via a web-based survey to the 105 physician panel members (âpanellistsâ) who directly engage in prostate cancer treatment decision-making. Herein, we present results for the 82 questions on topics 1â3.
Outcome measurements and statistical analysis
Consensus was defined as â„75% agreement, with strong consensus defined as â„90% agreement.
Results and limitations
The voting results reveal varying degrees of consensus, as is discussed in this article and shown in the detailed results in the Supplementary material. The findings reflect the opinions of an international panel of experts and did not incorporate a formal literature review and meta-analysis.
Conclusions
These voting results by a panel of international experts in advanced prostate cancer can help physicians and patients navigate controversial areas of clinical management for which high-level evidence is scant or conflicting. The findings can also help funders and policymakers prioritise areas for future research. Diagnostic and treatment decisions should always be individualised based on patient and cancer characteristics (disease extent and location, treatment history, comorbidities, and patient preferences) and should incorporate current and emerging clinical evidence, therapeutic guidelines, and logistic and economic factors. Enrolment in clinical trials is always strongly encouraged. Importantly, APCCC 2022 once again identified important gaps (areas of nonconsensus) that merit evaluation in specifically designed trials
Deep Learning based Modeling of Wireless Communication Channel with Fading
In the realm of wireless communication, stochastic modeling of channels is
instrumental for the assessment and design of operational systems. Deep
learning neural networks (DLNN), including generative adversarial networks
(GANs), are being used to approximate wireless Orthogonal frequency-division
multiplexing (OFDM) channels with fading and noise, using real measurement
data. These models primarily focus on channel output (y) distribution given
input x: p(y|x), limiting their application scope. DLNN channel models have
been tested predominantly on simple simulated channels. In this paper, we build
both GANs and feedforward neural networks (FNN) to approximate a more general
channel model, which is represented by a conditional probability density
function (PDF) of receiving signal or power of node receiving power Prx:
f_p_rx|d(()), where is communication distance. The stochastic models are
trained and tested for the impact of fading channels on transmissions of OFDM
QAM modulated signal and transmissions of general signal regardless of
modulations. New metrics are proposed for evaluation of modeling accuracy and
comparisons of the GAN-based model with the FNN-based model. Extensive
experiments on Nakagami fading channel show accuracy and the effectiveness of
the approaches.Comment: This work has been submitted to the IEEE for possible publication.
Copyright may be transferred without notice, after which this version may no
longer be accessibl
Joint effect of physical activity and sedentary behaviour on cardiovascular risk factors in Chilean adults
Background:
To investigate the associations between combined categories of moderate-to-vigorous physical activity (MVPA) and sedentary behaviour (SB) with markers of adiposity and cardiovascular risk in adults.
Methods:
Overall, 5040 participants (mean age 46.4 years and 59.3% women) from the cross-sectional Chilean National Health Survey 2009â2010 were included in this study. MVPA and SB were measured using the Global Physical Activity questionnaire. Four categories were computed using MVPA- and SB-specific cut-offs (âHigh-SB & Activeâ, âLow-SB & Activeâ, âHigh-SB & Inactiveâ and âLow-SB & Inactiveâ).
Results:
Compared to the reference group (âHigh-SB & Inactiveâ), those in âHigh-SB & Activeâ and âLow-SB & Activeâ were less likely to have an obese BMI (OR: 0.67 [0.54; 0.85], P = 0.0001 and 0.74 [0.59; 0.92] P = 0.0007, respectively) and less likely to have metabolic syndrome (OR: 0.63 [0.49; 0.82], P < 0.0001 and 0.72 [0.57; 0.91], P = 0.007), central obesity (OR: 0.79 [0.65; 0.96], P = 0.016 and 0.71 [0.59; 0.84], P < 0.0001), diabetes (OR: 0.45 [0.35; 0.59], P < 0.0001 and 0.44 [0.34; 0.56], P < 0.0001) and hypertension (OR: 0.52 [0.43; 0.63], P < 0.0001 and 0.60 [0.50; 0.72], P < 0.0001), respectively.
Conclusions:
Being physically active and spending less time in SBs was associated with lower adiposity and improvements in cardiovascular risk factors
Tax and Development: The Link between International Taxation, The Base Erosion Profit Shifting Project and The 2030 Sustainable Development Agenda.
The OECD-G20 project on Base Erosion and Profit Shifting (BEPS) is the largest reform of the international tax architecture in decades. The BEPS project aims to ensure that multinationals pay their taxes in the jurisdictions where they create value and where their economic activity takes place. When it is fully implemented, it will substantially alter the global governance architecture for taxation. This is a commendable goal, yet the BEPS project can be criticized for not sufficiently tailoring to the specific needs of developing countries. While it has made a laudable attempt to be more attentive towards developing countries with the creation of the BEPS inclusive framework, this concerns the implementation phase of BEPS. The agenda-setting and decision-making process only included the G20 and OECD countries. Against this background, it is unclear how and if the BEPS project considered the specific needs of developing countries, especially in light of the Sustainable Development Goals (SDGs). This paper will examine this issue by addressing the following questions: (i) Were the Sustainable Development Goals (SDGs) and the interests of developing countries to attract investment considered throughout the BEPS Process? (ii) What issues of international taxation, beyond BEPS, should be addressed to fulfill developing countries' domestic resource mobilization needs to achieve the 2030 Agenda for Sustainable Development. We conclude with a set of recommendations to the international global tax governance architecture to be more inclusive and responsive to development countriesâ needs.Seventh Framework Programme (FP7)758671Grenzen van fiscale soevereinitei
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