Root-Locus Analysis of Delayed First and Second Order Systems

For finite dimensional linear system the root-locus method is well established however for the case of delayed systems the method has some problems due to the transcendental term involved. This work intends to illustrate the problems that arises when a root-locus diagram is performed as well as to develop a Matlab function that provides the root-locus diagram for delayed low order systems. In this way, some comments about the problems that should be tackled to obtain a generalization of the computational method for delayed systems with real m poles and n zero

Root-Locus Analysis of Delayed First and Second Order Systems

For finite dimensional linear system the root-locus method is well established however for the case of delayed systems the method has some problems due to the transcendental term involved. This work intends to illustrate the problems that arises when a root-locus diagram is performed as well as to develop a Matlab function that provides the root-locus diagram for delayed low order systems. In this way, some comments about the problems that should be tackled to obtain a generalization of the computational method for delayed systems with real m poles and n zero

SARS-CoV-2 infection in patients with melanoma: results of the Spanish Melanoma Group registry

Background The Spanish Melanoma Group (GEM) developed a national registry of patients with melanoma infected by SARS-CoV-2 ( GRAVID ).Methods The main objective was to describe the COVID-19 fatality rate in patients with melanoma throughout the pandemic, as well as to explore the effect of melanoma treatment and tumor stage on the risk of COVID-19 complications. These are the final data of the register, including cases from February 2020 to September 2021.Results One hundred-fifty cases were registered. Median age was 68 years (range 6-95), 61 (40%) patients were females, and 63 (42%) patients had stage IV. Thirty-nine (26%) were on treatment with immunotherapy, and 17 (11%) with BRAF-MEK inhibitors. COVID-19 was resolved in 119 cases, including 85 (57%) patients cured, 15 (10%) that died due to melanoma, and 20 (13%) that died due to COVID-19. Only age over 60 years, cardiovascular disorders, and diabetes mellitus increased the risk of death due to COVID-19, but not advanced melanoma stage nor melanoma systemic therapies. Three waves have been covered by the register: February-May 2020, August-November 2020, and December 2020-April 2021. The first wave had the highest number of registered cases and COVID-19 mortality.Conclusion Tumor stage or melanoma treatments are non-significant prognostic factors for COVID-19 mortality. During the pandemic in Spain there was a downward trend in the number of patients registered across the waves, as well as in the severity of the infection

Human immunodeficiency virus continuum of care in 11 european union countries at the end of 2016 overall and by key population: Have we made progress?

Background. High uptake of antiretroviral treatment (ART) is essential to reduce human immunodeficiency virus (HIV) transmission and related mortality; however, gaps in care exist. We aimed to construct the continuum of HIV care (CoC) in 2016 in 11 European Union (EU) countries, overall and by key population and sex. To estimate progress toward the Joint United Nations Programme on HIV/AIDS (UNAIDS) 90-90-90 target, we compared 2016 to 2013 estimates for the same countries, representing 73% of the population in the region. Methods. A CoC with the following 4 stages was constructed: number of people living with HIV (PLHIV); proportion of PLHIV diagnosed; proportion of those diagnosed who ever initiated ART; and proportion of those ever treated who achieved viral suppression at their last visit. Results. We estimated that 87% of PLHIV were diagnosed; 92% of those diagnosed had ever initiated ART; and 91% of those ever on ART, or 73% of all PLHIV, were virally suppressed. Corresponding figures for men having sex with men were: 86%, 93%, 93%, 74%; for people who inject drugs: 94%, 88%, 85%, 70%; and for heterosexuals: 86%, 92%, 91%, 72%. The proportion suppressed of all PLHIV ranged from 59% to 86% across countries. Conclusions. The EU is close to the 90-90-90 target and achieved the UNAIDS target of 73% of all PLHIV virally suppressed, significant progress since 2013 when 60% of all PLHIV were virally suppressed. Strengthening of testing programs and treatment support, along with prevention interventions, are needed to achieve HIV epidemic control