A
bstract
We present a generalization of the relativistic, finite-volume, three-particle quantization condition for non-identical pions in isosymmetric QCD. The resulting formalism allows one to use ...discrete finite-volume energies, determined using lattice QCD, to constrain scattering amplitudes for all possible values of two- and three-pion isospin. As for the case of identical pions considered previously, the result splits into two steps: the first defines a non-perturbative function with roots equal to the allowed energies,
E
n
(
L
), in a given cubic volume with side-length
L
. This function depends on an intermediate three-body quantity, denoted
K
df
,
3
,
which can thus be constrained from lattice QCD in- put. The second step is a set of integral equations relating
K
df
,
3
to the physical scattering amplitude, ℳ
3
. Both of the key relations,
E
n
(
L
)
↔
K
df
,
3
and
K
df
,
3
↔
ℳ
3
,
are shown to be block-diagonal in the basis of definite three-pion isospin,
I
πππ
, so that one in fact recovers four independent relations, corresponding to
I
πππ
= 0
,
1
,
2
,
3. We also provide the generalized threshold expansion of
K
df
,
3
for all channels, as well as parameterizations for all three-pion resonances present for
I
πππ
= 0 and
I
πππ
= 1. As an example of the utility of the generalized formalism, we present a toy implementation of the quantization condition for
I
πππ
= 0, focusing on the quantum numbers of the
ω
and
h
1
resonances.
A
bstract
We present an implementation of the relativistic three-particle quantization condition including both
s
- and
d
-wave two-particle channels. For this, we develop a systematic expansion of ...the three-particle K matrix,
K
df,3
, about threshold, which is the generalization of the effective range expansion of the two-particle K matrix,
K
2
. Relativistic invariance plays an important role in this expansion. We find that
d
-wave two-particle channels enter first at quadratic order. We explain how to implement the resulting multichannel quantization condition, and present several examples of its application. We derive the leading dependence of the threshold three-particle state on the two-particle
d
-wave scattering amplitude, and use this to test our implementation. We show how strong two-particle
d
-wave interactions can lead to significant effects on the finite-volume three-particle spectrum, including the possibility of a generalized three-particle Efimov-like bound state. We also explore the application to the 3
π
+
system, which is accessible to lattice QCD simulations, where we study the sensitivity of the spectrum to the components of
K
df,3
. Finally, we investigate the circumstances under which the quantization condition has unphysical solutions.
This study investigates the satisfaction and adequacy of citizens through the expected quality and perceived quality in the areas of planning and territorial viability, experience in the provision of ...municipal services and citizen experience in environmental issues, in order to provide tools for territorial decision making for the citizens' well-being. In our research PLS software is used for the analysis of hypotheses. A questionnaire was delivered to a sample of 521 citizens, representing the spectrum of the population, and the statistical study of the responses yielded results on citizen satisfaction and loyalty. Our research includes the study of moderating effects on the causal ratio of perceived value and satisfaction in territorial planning and viability, the perceived quality in the provision of municipal services and the perceived quality in the citizen experience in the environmental management of the territory on the value relationship perceived by the citizen and general satisfaction. A second objective of the study is to see if there are significant differences in the hypotheses raised by gender by performing a multigroup analysis. This difference has been appreciated in two of the hypotheses. The study shows that the policies exercised by the territorial managers of the different areas have a significant influence on the value perceived by citizens, satisfaction and loyalty, which shape their general well-being. Areas for improvement in territorial policies and municipal services such as citizen security, air quality, public lighting and sports services have been identified. Knowing these shortcomings allows politicians to focus their efforts on improving the quality of life in cities.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Bacterial phytopathogens living on the surface or within plant tissues may experience oxidative stress because of the triggered plant defense responses. Although it has been suggested that polyamines ...can defend bacteria from this stress, the mechanism behind this action is not entirely understood. In this study, we investigated the effects of oxidative stress on the polyamine homeostasis of the plant pathogen Pseudomonas syringae and the functions of these compounds in bacterial stress tolerance. We demonstrated that bacteria respond to H
O
by increasing the external levels of the polyamine putrescine while maintaining the inner concentrations of this compound as well as the analogue amine spermidine. In line with this, adding exogenous putrescine to media increased bacterial tolerance to H
O
. Deletion of arginine decarboxylase (speA) and ornithine decarboxylate (speC), prevented the synthesis of putrescine and augmented susceptibility to H
O
, whereas targeting spermidine synthesis alone through deletion of spermidine synthase (speE) increased the level of extracellular putrescine and enhanced H
O
tolerance. Further research demonstrated that the increased tolerance of the ΔspeE mutant correlated with higher expression of H
O
-degrading catalases and enhanced outer cell membrane stability. Thus, this work demonstrates previously unrecognized connections between bacterial defense mechanisms against oxidative stress and the polyamine metabolism.
A
bstract
We present a general method for deriving the energy shift of an interacting system of
N
spinless particles in a finite volume. To this end, we use the nonrelativistic effective field theory ...(NREFT), and match the pertinent low-energy constants to the scattering amplitudes. Relativistic corrections are explicitly included up to a given order in the 1/
L
expansion. We apply this method to obtain the ground state of
N
particles, and the first excited state of two and three particles to order
L
−
6
in terms of the threshold parameters of the two- and three-particle relativistic scattering amplitudes. We use these expressions to analyze the
N
-particle ground state energy shift in the complex
φ
4
theory.
A
bstract
We derive relations between finite-volume matrix elements and infinite-volume decay amplitudes, for processes with three spinless, degenerate and either identical or non-identical particles ...in the final state. This generalizes the Lellouch-Lüscher relation for two-particle decays and provides a strategy for extracting three-hadron decay amplitudes using lattice QCD. Unlike for two particles, even in the simplest approximation, one must solve integral equations to obtain the physical decay amplitude, a consequence of the nontrivial finite-state interactions. We first derive the result in a simplified theory with three identical particles, and then present the generalizations needed to study phenomenologically relevant three-pion decays. The specific processes we discuss are the CP-violating
K
→ 3
π
weak decay, the isospin-breaking
η
→ 3
π
QCD transition, and the electromagnetic
γ
*
→ 3
π
amplitudes that enter the calculation of the hadronic vacuum polarization contribution to muonic
g −
2.
Abstract
Endophytic bacterial communities of tomato leaves were analyzed by 16S-rRNA gene pyrosequencing and compared to rhizosphere communities. Leaf endophytes mainly comprised five phyla, among ...which Proteobacteria was the most represented (90%), followed by Actinobacteria (1,5%), Planctomycetes (1,4%), Verrucomicrobia (1,1%), and Acidobacteria (0,5%). Gammaproteobacteria was the most abundant class of Proteobacteria (84%), while Alphaproteobacteria and Betaproteobacteria represented 12% and 4% of this phylum, respectively. Rarefaction curves for endophytic bacteria saturated at 80 OTUs, indicating a lower diversity as compared to rhizosphere samples (> 1700 OTUs). Hierarchical clustering also revealed that leaf endophytic communities strongly differed from rhizospheric ones. Some OTUs assigned to Bacillus, Stenotrophomonas, and Acinetobacter, as well as some unclassified Enterobacteriaceae were specific for the endophytic community, probably representing bacteria specialized in colonizing this niche. On the other hand, some OTUs detected in the leaf endophytic community were also present in the rhizosphere, probably representing soil bacteria that endophytically colonize leaves. As a whole, this study describes the composition of the endophytic bacterial communities of tomato leaves, identifying a variety of genera that could exert multiple effects on growth and health of tomato plants.
A culture-independent approach was used to analyze the structure and diversity of bacterial communities that endophytically colonize leaves of cultivated tomato.
Topological sampling through windings Albandea, David; Hernández, Pilar; Ramos, Alberto ...
European physical journal. C, Particles and fields,
10/2021, Letnik:
81, Številka:
10
Journal Article
Recenzirano
Odprti dostop
We propose a modification of the Hybrid Monte Carlo (HMC) algorithm that overcomes the topological freezing of a two-dimensional
U
(1) gauge theory with and without fermion content. This algorithm ...includes reversible jumps between topological sectors – winding steps – combined with standard HMC steps. The full algorithm is referred to as winding HMC (wHMC), and it shows an improved behaviour of the autocorrelation time towards the continuum limit. We find excellent agreement between the wHMC estimates of the plaquette and topological susceptibility and the analytical predictions in the
U
(1) pure gauge theory, which are known even at finite
β
. We also study the expectation values in fixed topological sectors using both HMC and wHMC, with and without fermions. Even when topology is frozen in HMC – leading to significant deviations in topological as well as non-topological quantities – the two algorithms agree on the fixed-topology averages. Finally, we briefly compare the wHMC algorithm results to those obtained with master-field simulations of size
L
∼
8
×
10
3
.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A
bstract
Recently, the formalism needed to relate the finite-volume spectrum of systems of nondegenerate spinless particles has been derived. In this work we discuss a range of issues that arise ...when implementing this formalism in practice, provide further theoretical results that can be used to check the implementation, and make available codes for implementing the three-particle quantization condition. Specifically, we discuss the need to modify the upper limit of the cutoff function due to the fact that the left-hand cut in the scattering amplitudes for two nondegenerate particles moves closer to threshold; we describe the decomposition of the three-particle amplitude
K
df
,
3
into the matrix basis used in the quantization condition, including both
s
and
p
waves, with the latter arising in the amplitude for two nondegenerate particles; we derive the threshold expansion for the lightest three-particle state in the rest frame up to
O
(1
/L
5
); and we calculate the leading-order predictions in chiral perturbation theory for
K
df
,
3
in the
π
+
π
+
K
+
and
π
+
K
+
K
+
systems. We focus mainly on systems with two identical particles plus a third that is different (“2+1” systems). We describe the formalism in full detail, and present numerical explorations in toy models, in particular checking that the results agree with the threshold expansion, and making a prediction for the spectrum of
π
+
π
+
K
+
levels using the two- and three-particle interactions predicted by chiral perturbation theory.
A
bstract
In this work, we use an extension of the quantization condition, given in ref.
1
, to numerically explore the finite-volume spectrum of three relativistic particles, in the case that ...two-particle subsets are either resonant or bound. The original form of the relativistic three-particle quantization condition was derived under a technical assumption on the two- particle K matrix that required the absence of two-particle bound states or narrow two- particle resonances. Here we describe how this restriction can be lifted in a simple way using the freedom in the definition of the K-matrix-like quantity that enters the quantization condition. With this in hand, we extend previous numerical studies of the quantization condition to explore the finite-volume signature for a variety of two- and three-particle interactions. We determine the spectrum for parameters such that the system contains both dimers (two-particle bound states) and one or more trimers (in which all three particles are bound), and also for cases where the two-particle subchannel is resonant. We also show how the quantization condition provides a tool for determining infinite-volume dimer- particle scattering amplitudes for energies below the dimer breakup. We illustrate this for a series of examples, including one that parallels physical deuteron-nucleon scattering. All calculations presented here are restricted to the case of three identical scalar particles.
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