46,065 research outputs found
Scattering and bound states of spin-0 particles in a nonminimal vector double-step potential
The problem of spin-0 particles subject to a nonminimal vector double-step
potential is explored in the context of the Duffin-Kemmer-Petiau theory.
Surprisingly, one can never have an incident wave totally reflected and the
transmission amplitude has complex poles corresponding to bound states. The
interesting special case of bosons embedded in a sign potential with its unique
bound-state solution is analyzed as a limiting case.Comment: 1 figur
Lactobacillus crispatus as the etiological agent in cytolytic vaginosis
Introduction: Lactobacillus spp. dominate the vaginal niche but can also be involved in other vaginal dysbiosis, such as cytolytic vaginosis (CV), which remains poorly studied. It is characterized by a cryptic symptomatology, that often confounds the clinic.
Goals: The aim of this work was to search for the etiological agent of CV, by studying the vaginal microbiome and metabolomics of women afflicted with this disease and compare it with women with other clinical diagnostic.
Methods: Twenty-one vaginal washes have been collected from women attending a gynaecology consultation of a private clinic. The samples were categorized according with clinical diagnosis at the time of sampling (CV, 11; vulvovaginal candidosis, 8; Healthy, 2). The distribution of bacterial species, and their prevalence was assessed by next-generation sequencing of the 16S V4 region. In addition, total lactate D-lactic acid and L-lactic acid was quantified in all washes by a commercial kit, as well as lactate dehydrogenase (LDH) activity.
Results: L. crispatus was dominant (>70%) in all CV samples. Lactate was increased in CV in comparison with other cases. The presence of D-lactic acid isomer was associated with presence of L. crispatus. LDH activity was increased in vaginal washes that tested positive for the presence of L. crispatus, however no direct association was found with CV cases.
Discussion/Conclusions: The microbiome of women afflicted with CV was dominated in all cases by L. crispatus, contrarily with the results obtained for women diagnosed with other clinical symptomatology. In addition, the finding that an increase in D-lactic acid is associated with CV patients can be related to the role of L. crispatus in CV. The determination of LDH activity did not correlate exclusively with CV cases. On the other hand, D-lactic acid and total lactate quantification could be used as a valuable biomarker to diagnose this cryptic vaginal infection.info:eu-repo/semantics/publishedVersio
Susceptibility of a two-level atom near an isotropic photonic band edge: transparency and band edge profile reconstruction
We discuss the necessary conditions for a two-level system in the presence of
an isotropic band edge to be transparent to a probe laser field. The two-level
atom is transparent whenever it is coupled to a reservoir constituted of two
parts - a flat and a non-flat density of modes representing a PBG structure. A
proposal on the reconstruction of the band edge profile from the experimentally
measured susceptibility is also presented.Comment: 15 pages, 3 figure
Coherence and incoherence in extended broad band triplet interaction
In the present analysis we study the transition from coherent to incoherent
dynamics in a nonlinear triplet of broad band combs of waves. Expanding the
analysis of previous works, this paper investigates what happens when the band
of available modes is much larger than that of the initial narrower combs
within which the nonlinear interaction is not subjected to selection rules
involving wave momenta. Here selection rules are present and active, and we
examine how and when coherence can be defined.Comment: 6 pages, 2 figure
Treatment of the infrared contribution: NLO QED evolution as a pedagogic example
We show that the conventional prescription used for DGLAP parton evolution at
NLO has an inconsistent treatment of the contribution from the infrared (IR)
region. We illustrate the problem by studying the simple example of QED
evolution, treating the electron and photon as partons. The deficiency is not
present in a physical approach which removes the IR divergency and allows
calculation in the normal 4-dimensional space.Comment: 15 pages, 2 figures, erratum at the end of the articl
Improving the Drell-Yan probe of small x partons at the LHC via a k_t cut
We show that the observation of the Drell-Yan production of low-mass
lepton-pairs (M 3) at the LHC can make a
direct measurement of parton distribution functions (PDFs) in the low x region,
x < 10^{-4}. We describe a procedure that greatly reduces the sensitivity of
the predictions to the choice of the factorization scale and, in particular,
show how, by imposing a cutoff on the transverse momentum of the lepton-pair,
the data are able to probe PDFs in the important low scale, low x domain. We
include the effects of the Sudakov suppression factor.Comment: 14 pages, 5 figures, version to be published in EPJC, with expanded
explanatio
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