39,153 research outputs found
Takotsubo Syndrome and COVID-19: Associations and Implications.
Incidence of cardiovascular complications has increased during the COVID-19 (Coronavirus disease 2019) pandemic, both population-wide and in patients diagnosed with the disease. This increase has presented complications in patient care, leading to increased hospitalizations, adverse outcomes, and medical costs. A condition of interest is takotsubo syndrome, which may be associated with the novel coronavirus. To understand this connection, a narrative review was performed by analyzing primary studies and case reports available. The findings showed increased incidence of takotsubo cardiomyopathy in both the general population and COVID-19 patients. Proposed mechanisms for the linkage include generalized increases in psychological distress, the cytokine storm, increased sympathetic responses in COVID-19 patients, and microvascular dysfunction. Moreover, natural disasters are noted as likely being associated with increases of takotsubo syndrome. As the pandemic continues, treating COVID-19 as a systemic condition is imperative, with the increase in takotsubo syndrome marking a significant impact of the novel coronavirus
Impersonating the Standard Model Higgs Boson: Alignment without Decoupling
In models with an extended Higgs sector there exists an alignment limit, in
which the lightest CP-even Higgs boson mimics the Standard Model Higgs. The
alignment limit is commonly associated with the decoupling limit, where all
non-standard scalars are significantly heavier than the boson. However,
alignment can occur irrespective of the mass scale of the rest of the Higgs
sector. In this work we discuss the general conditions that lead to "alignment
without decoupling", therefore allowing for the existence of additional
non-standard Higgs bosons at the weak scale. The values of for
which this happens are derived in terms of the effective Higgs quartic
couplings in general two-Higgs-doublet models as well as in supersymmetric
theories, including the MSSM and the NMSSM. Moreover, we study the information
encoded in the variations of the SM Higgs-fermion couplings to explore regions
in the parameter space.Comment: 42 Pages, 8 figure
Higgs Portals for Thermal Dark Matter - EFT Perspectives and the NMSSM -
We analyze a low energy effective model of Dark Matter in which the thermal
relic density is provided by a singlet Majorana fermion which interacts with
the Higgs fields via higher dimensional operators. Direct detection signatures
may be reduced if blind spot solutions exist, which naturally appear in models
with extended Higgs sectors. Explicit mass terms for the Majorana fermion can
be forbidden by a symmetry, which in addition leads to a reduction of the
number of higher dimensional operators. Moreover, a weak scale mass for the
Majorana fermion is naturally obtained from the vacuum expectation value of a
scalar singlet field. The proper relic density may be obtained by the
-channel interchange of Higgs and gauge bosons, with the longitudinal mode
of the boson (the neutral Goldstone mode) playing a relevant role in the
annihilation process. This model shares many properties with the
Next-to-Minimal Supersymmetric extension of the Standard Model (NMSSM) with
light singlinos and heavy scalar and gauge superpartners. In order to test the
validity of the low energy effective field theory, we compare its predictions
with those of the ultraviolet complete NMSSM. Extending our framework to
include neutral Majorana fermions, analogous to the bino in the NMSSM, we
find the appearance of a new bino-singlino well tempered Dark Matter region.Comment: 42 pages, 14 figures. v2: added references, published in JHE
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