54 research outputs found
Comment on "Effective of the q-deformed pseudoscalar magnetic field on the charge carriers in graphene"
We point out a misleading treatment in a recent paper published in this
Journal [J. Math. Phys. (2016) 57, 082105] concerning solutions for the
two-dimensional Dirac-Weyl equation with a q-deformed pseudoscalar magnetic
barrier. The authors misunderstood the full meaning of the potential and made
erroneous calculations, this fact jeopardizes the main results in this system.Comment: 7 pages, 2 figure
Effects of a uniform magnetic field on twisted graphene nanoribbons
In the present work, the relativistic quantum motion of massless fermions in
a helicoidal graphene nanoribbon under the influence of a uniform magnetic
field is investigated. Considering a uniform magnetic field () aligned along
the axis of helicoid, this problem is explored in the context of Dirac equation
in a curved space-time. As this system does not support exact solutions due to
considered background, the bound-state solutions and local density of state
(LDOS) are obtained numerically by means of the Numerov method. The combined
effects of width of the nanoribbon (), length of ribbon (), twist
parameter () and on the equations of motion and local density of
states (LDOS) are analyzed and discussed. It is verified that the presence of
produces a constant minimum value of local density of state on the axis of
helicoid, which is possible only for values large enough of , in
contrast to the case for already studied in the literature.Comment: 10 pages, 7 figure
Identifying and preventing burnout in young oncologists, an overwhelming challenge in the COVID-19 era: a study of the Spanish Society of Medical Oncology (SEOM)
COVID-19; Esgotament professional; Oncòlegs jovesCOVID-19; Agotamiento profesional; Oncólogos jóvenesCOVID-19; Professional burnout; Young oncologistsBackground
Young oncologists are at particular risk of professional burnout, and this could have a significant impact on their health and care of their patients. The coronavirus disease 2019 (COVID-19) pandemic has forced rapid changes in professionals' jobs and training, with the consequent physical and psychological effects. We aimed to characterize burnout levels and determinants in young oncologists, and the effects of the pandemic on their training and health.
Methods
Two online surveys were conducted among oncology residents and young oncology specialists in Spain. The first addressed professional burnout and its determinants before the COVID-19 pandemic, while the second analyzed the impact of the pandemic on health care organization, training, and physical and psychological health in the same population.
Results
In total, 243 respondents completed the first survey, and 263 the second; 25.1% reported significant levels of professional burnout. Burnout was more common among medical oncology residents (28.2%), mainly in their second year of training. It was significantly associated with a poor work–life balance, inadequate vacation time, and the burnout score. Nearly three-quarters of respondents (72%) were reassigned to COVID-19 care and 84.3% of residents missed part of their training rotations. Overall, 17.2% of this population reported that they had contracted COVID-19, 37.3% had scores indicating anxiety, and 30.4% moderate to severe depression. Almost a quarter of young oncologists (23.3%) had doubts about their medical vocation.
Conclusions
Burnout affects a considerable number of young oncologists. The COVID-19 pandemic has had a profound impact on causes of burnout, making it even more necessary to periodically monitor it to define appropriate detection and prevention strategies.This project received funding from the Spanish Society of Medical Oncology (SEOM)
Effects of a Uniform Magnetic Field on Twisted Graphene Nanoribbons
In the present work, the relativistic quantum motion of massless fermions in a helicoidal graphene nanoribbon under the influence of a uniform magnetic field is investigated. Considering a uniform magnetic field (B) aligned along the axis of helicoid, this problem is explored in the context of Dirac equation in a curved space-time. As this system does not support exact solutions due to considered background, the bound-state solutions and local density of states (LDOS) are obtained numerically by means of the Numerov method. The combined effects of width of the nanoribbon (D), length of ribbon (L), twist parameter (ω), and B on the equations of motion and LDOS are analyzed and discussed. It is verified that the presence of B produces a constant minimum value of local density of state on the axis of helicoid, which is possible only for values large enough of ω, in contrast to the case for
already studied in the literature
An International Comparison of Presentation, Outcomes and CORONET Predictive Score Performance in Patients with Cancer Presenting with COVID-19 across Different Pandemic Waves.
Patients with cancer have been shown to have increased risk of COVID-19 severity. We previously built and validated the COVID-19 Risk in Oncology Evaluation Tool (CORONET) to predict the likely severity of COVID-19 in patients with active cancer who present to hospital. We assessed the differences in presentation and outcomes of patients with cancer and COVID-19, depending on the wave of the pandemic. We examined differences in features at presentation and outcomes in patients worldwide, depending on the waves of the pandemic: wave 1 D614G (n = 1430), wave 2 Alpha (n = 475), and wave 4 Omicron variant (n = 63, UK and Spain only). The performance of CORONET was evaluated on 258, 48, and 54 patients for each wave, respectively. We found that mortality rates were reduced in subsequent waves. The majority of patients were vaccinated in wave 4, and 94% were treated with steroids if they required oxygen. The stages of cancer and the median ages of patients significantly differed, but features associated with worse COVID-19 outcomes remained predictive and did not differ between waves. The CORONET tool performed well in all waves, with scores in an area under the curve (AUC) of >0.72. We concluded that patients with cancer who present to hospital with COVID-19 have similar features of severity, which remain discriminatory despite differences in variants and vaccination status. Survival improved following the first wave of the pandemic, which may be associated with vaccination and the increased steroid use in those patients requiring oxygen. The CORONET model demonstrated good performance, independent of the SARS-CoV-2 variants
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