Flamelet based chemical reduction techniques are very promising methods for efficient and accurate modeling of premixed flames. Over the years the Flamelet Generated Manifold (FGM) technique has been ...developed by the Combustion Technology Group of Eindhoven University of Technology. Current state-of-the-art of FGM for the modeling of premixed and partially-premixed flames is reviewed. The fundamental basis of FGM consists of a generalized description of the flame front in a (possibly moving) flame-adapted coordinate system. The basic nature of the generalized flamelet model is that effects of strong stretch in turbulent flames are taken into account by resolving the detailed structure of flame stretch and curvature inside the flame front. The generalized flamelet model, which forms the basis on which FGM is built, is derived in Part I. To be able to validate numerical results of flames obtained with full chemistry and obtained from FGM, it is important that the generalized flamelet model is analyzed further. This is done by investigating the impact of strong stretch, curvature and preferential diffusion effects on the flame dynamics as described by the local mass burning rate. This so-called strong stretch theory is derived and analyzed in Part I, as well as multiple simplifications of it, to compare the strong stretch theory with existing stretch theories. The results compare well with numerical results for flames with thin reaction layers, but described by multiple-species transport and chemistry. This opens the way to use the generalized flamelet model as a firm basis for applying FGM in strongly stretched laminar and turbulent flames in Part II. The complete FGM model is derived first and the use of FGM in practice is reviewed. The FGM model is then validated by studying effects of flame stretch, heat loss, and changes in elements, as well as NO formation. The application to direct numerical simulations of turbulent flames is subsequently studied and validated using the strong stretch theory. It is shown that the generalized flamelet model still holds even in case of strong stretch and curvature effects, at least as long as the reaction layer is dominated by reaction and diffusion phenomena and not perturbed too much by stretch related perturbations. The FGM model then still performs very well with a low number of control variables. Turbulent flames with strong preferential diffusion effects can also be modeled efficiently with an FGM model using a single additional control variable for the changes in element mass fractions and enthalpy. Finally FGM is applied to the modeling of turbulent flames using LES and RANS flow solvers. For these cases, the flame front structure is not resolved anymore and unresolved terms need to be modeled. A common approach to include unresolved turbulent fluctuations is the presumed probability density function (PDF) approach. The validity of this FGM-PDF approach is discussed for a few test cases with increasing level of complexity.
In Ref. Donini and Marimón (Eur Phys J C 76:696,
arXiv:1609.05654
, 2016), an experimental setup aiming at the measurement of deviations from the Newtonian
1
/
r
2
distance dependence of ...gravitational interactions was proposed. The theoretical idea behind this setup was to study the trajectories of a “Satellite” with a mass
m
S
∼
O
(
10
-
9
)
g around a “Planet” with mass
m
P
∈
10
-
7
,
10
-
5
g, looking for precession of the orbit. The observation of such feature induced by gravitational interactions would be an unambiguous indication of a gravitational potential with terms different from 1/
r
and, thus, a powerful tool to detect deviations from Newton’s
1
/
r
2
law. In this paper we optimize the proposed setup in order to achieve maximal sensitivity to look for such
Beyond-Newtonian
corrections. We then study in detail possible background sources that could induce precession and quantify their impact on the achievable sensitivity. We finally conclude that a dynamical measurement of deviations from newtonianity can test Yukawa-like corrections to the 1/
r
potential with strength as low as
α
∼
10
-
2
for distances as small as
λ
∼
10
μ
m.
A
bstract
We study the constraints imposed by neutrino oscillation experiments on the minimal extension of the Standard Model that can explain neutrino masses, which requires the addition of just two ...singlet Weyl fermions. The most general renormalizable couplings of this model imply generically four massive neutrino mass eigenstates while one remains massless: it is therefore a minimal 3 + 2 model. The possibility to account for the confirmed solar, atmospheric and long-baseline oscillations, together with the LSND/MiniBooNE and reactor anomalies is addressed. We find that the minimal model can fit oscillation data including the anomalies better than the standard 3
ν
model and similarly to the 3 + 2 phenomenological models, even though the number of free parameters is much smaller than in the latter. Accounting for the anomalies in the minimal model favours a normal hierarchy of the light states and requires a large reactor angle, in agreement with recent measurements. Our analysis of the model employs a new parametrization of seesaw models that extends the Casas-Ibarra one to regimes where higher order corrections in the light-heavy mixings are significant.
A novel experimental setup to measure deviations from the
1
/
r
2
distance dependence of Newtonian gravity was proposed in Donini and Marimón (Eur Phys J C 76:696, 2016). The underlying theoretical ...idea was to study the orbits of a microscopically-sized planetary system composed of a “Satellite”, with mass
m
S
∼
O
(
10
-
9
)
g, and a “Planet”, with mass
M
P
∼
O
(
10
-
5
)
g at an initial distance of hundreds of microns. The detection of precession of the orbit in this system would be an unambiguous indication of a central potential with terms that scale with the distance differently from 1/
r
. This is a huge advantage with respect to the measurement of the absolute strength of the attraction between two bodies, as most electrically-induced background potentials do indeed scale as 1/
r
. Detection of orbit precession is unaffected by these effects, allowing for better sensitivities. In Baeza-Ballesteros et al. (Eur Phys J C 82:154, 2022), the impact of other subleading backgrounds that may induce orbit precession, such as, e.g., the electrical Casimir force or general relativity, was studied in detail. It was found that the proposed setup could test Yukawa-like corrections,
α
×
exp
(
-
r
/
λ
)
,
to the 1/
r
potential with couplings as low as
α
∼
10
-
2
for distances as small as
λ
∼
10
μ
m, improving by roughly an order of magnitude present bounds. In this paper, we start to move from a theoretical study of the proposal to a more realistic implementation of the experimental setup. As a first step, we study the impact of air viscosity on the proposed setup and see how the setup should be modified in order to preserve the theoretical sensitivity achieved in Donini and Marimón (2016) and Baeza-Ballesteros et al. (2022).
A
bstract
We perform a comparison of the different future neutrino oscillation experiments based on the achievable precision in the determination of the fundamental parameters
θ
13
and the CP phase,
...δ
, assuming that
θ
13
is in the range indicated by the recent Daya Bay measurement. We study the non-trivial dependence of the error on
δ
on its true value. When matter effects are small, the largest error is found at the points where CP violation is maximal, and the smallest at the CP conserving points. The situation is different when matter effects are sizable. As a result of this effect, the comparison of the physics reach of different experiments on the basis of the CP discovery potential, as usually done, can be misleading. We have compared various proposed super-beam, beta-beam and neutrino factory setups on the basis of the relative precision of
θ
13
and the error on
δ
. Neutrino factories, both high-energy or low-energy, outperform alternative beam technologies. An ultimate precision on
θ
13
below 3% and an error on
δ
of ≤ 7° at 1
σ
(1 d.o.f.) can be obtained at a neutrino factory.
The objective of this study was to compare the 7th and the 8th edition of American Joint Committee on Cancer staging system (AJCC TNM) in terms of better stratification in our gastric cancer resected ...patients.
A retrospective analysis of a single western center series was made. Patients who underwent surgery from January 2004 to December 2016 were enrolled in the study. We compared survival rates across patients classified according to the 7th and the 8th AJCC TNM staging system.
Among 295 patients we observed 9.8% stage migration according the 8th edition. Of these 2.1% and 7.9% of patients showed respectively a higher and a lower stage.
5 years Overall Survival (5Y-OS) according to the 8th edition for stage IIIB and IIIC were 32% versus 9% showing a better stratification compared to the 7th edition in which 5Y-OS were respectively 26% versus 22%.
Restaging system seems to improve survival rate discrimination in particular comparing stage IIIB and stage IIIC; whereas in stage IIIA this is not so clear.
More studies are necessary to confirm these data.
Background
The introduction of complete mesocolic excision (CME) for right colon cancer has raised an important discussion in relation to the extent of colic and mesenteric resection, and the impact ...this may have on lymph node yield. As uncertainty remains regarding the usefulness of and indications for right hemicolectomy with CME and the benefits of CME compared with a traditional approach, the purpose of this meta-analysis is to compare the two procedures in terms of safety, lymph node yield and oncological outcome.
Methods
We performed a systematic review of the literature from 2009 up to March 15th, 2020 according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Two hundred eighty-one publications were evaluated, and 17 met the inclusion criteria and were included. Primary endpoints analysed were anastomotic leak rate, blood loss, number of harvested lymph nodes, 3- and 5-year oncologic outcomes. Secondary outcomes were operating time, conversion, intraoperative complications, reoperation rate, overall and Clavien–Dindo grade 3–4 postoperative complications.
Results
In terms of safety, right hemicolectomy with CME is not inferior to the standard procedure when comparing rates of anastomotic leak (RR 0.82, 95% CI 0.38–1.79), blood loss (MD −32.48, 95% CI −98.54 to −33.58), overall postoperative complications (RR 0.82, 95% CI 0.67–1.00), Clavien–Dindo grade III–IV postoperative complications (RR 1.36, 95% CI 0.82–2.28) and reoperation rate (RR 0.65, 95% CI 0.26–1.75). Traditional surgery is associated with a shorter operating time (MD 16.43, 95% CI 4.27–28.60) and lower conversion from laparoscopic to open approach (RR 1.72, 95% CI 1.00–2.96). In terms of oncologic outcomes, right hemicolectomy with CME leads to a higher lymph node yield than traditional surgery (MD 7.05, 95% CI 4.06–10.04). Results of statistical analysis comparing 3-year overall survival and 5-year disease-free survival were better in the CME group, RR 0.42, 95% CI 0.27–0.66 and RR 0.36, 95% CI 0.17–0.56, respectively.
Conclusions
Right hemicolectomy with CME is not inferior to traditional surgery in terms of safety and has a greater lymph node yield when compared with traditional surgery. Moreover, right-sided CME is associated with better overall and disease-free survival.
Aims.
In the presence of a sufficient amount of target material,
γ
-rays can be used as a tracer in the search for sources of Galactic cosmic rays (CRs). Here we present deep observations of the ...Galactic center (GC) region with the MAGIC telescopes and use them to infer the underlying CR distribution and to study the alleged PeV proton accelerator at the center of our Galaxy.
Methods.
We used data from ≈100 h observations of the GC region conducted with the MAGIC telescopes over five years (from 2012 to 2017). Those were collected at high zenith angles (58−70 deg), leading to a larger energy threshold, but also an increased effective collection area compared to low zenith observations. Using recently developed software tools, we derived the instrument response and background models required for extracting the diffuse emission in the region. We used existing measurements of the gas distribution in the GC region to derive the underlying distribution of CRs. We present a discussion of the associated biases and limitations of such an approach.
Results.
We obtain a significant detection for all four model components used to fit our data (Sgr A*, “Arc”, G0.9+0.1, and an extended component for the Galactic Ridge). We observe no significant difference between the
γ
-ray spectra of the immediate GC surroundings, which we model as a point source (Sgr A*) and the Galactic Ridge. The latter can be described as a power-law with index 2 and an exponential cut-off at around 20 TeV with the significance of the cut-off being only 2
σ
. The derived cosmic-ray profile hints to a peak at the GC position and with a measured profile index of 1.2 ± 0.3 is consistent with the 1/
r
radial distance scaling law, which supports the hypothesis of a CR accelerator at the GC. We argue that the measurements of this profile are presently limited by our knowledge of the gas distribution in the GC vicinity.
We report the detection of pulsed gamma-ray emission from the Geminga pulsar (PSR J0633+1746) between 15 GeV and 75 GeV. This is the first time a middle-aged pulsar has been detected up to these ...energies. Observations were carried out with the MAGIC telescopes between 2017 and 2019 using the low-energy threshold Sum-Trigger-II system. After quality selection cuts, ∼80 h of observational data were used for this analysis. To compare with the emission at lower energies below the sensitivity range of MAGIC, 11 years of
Fermi
-LAT data above 100 MeV were also analysed. From the two pulses per rotation seen by
Fermi
-LAT, only the second one,
P
2, is detected in the MAGIC energy range, with a significance of 6.3
σ
. The spectrum measured by MAGIC is well-represented by a simple power law of spectral index Γ = 5.62 ± 0.54, which smoothly extends the
Fermi
-LAT spectrum. A joint fit to MAGIC and
Fermi
-LAT data rules out the existence of a sub-exponential cut-off in the combined energy range at the 3.6
σ
significance level. The power-law tail emission detected by MAGIC is interpreted as the transition from curvature radiation to Inverse Compton Scattering of particles accelerated in the northern outer gap.
Minimally invasive surgery for advanced gastric cancer: are we sure? Graziosi, L.; Marino, E.; Donini, A.
Gastric cancer : official journal of the International Gastric Cancer Association and the Japanese Gastric Cancer Association,
11/2017, Volume:
20, Issue:
6
Journal Article
PDF
