Ecuaciones lineales en diferencias. Aplicaciones a la empresa y la economía

Este trabajo es una introducción desde el punto de vista matemático a las ecuaciones en diferencias, especialmente a las lineales, encaminado principalmente a resolver problemas económicos y empresariales cimentados en este tipo de ecuaciones. A pesar de ello, su contenido y exposición ha sido desarrollado para que pueda servir como apuntes de trabajo a cualquier persona que quiera introducirse en el mundo de las ecuaciones en diferencias. Las aplicaciones que aquí se plantean pueden ser comprendidas sin necesidad de grandes conocimientos empresariales o económicos. Algunos planteamientos económicos utilizan ecuaciones en diferencias muy simples, por lo que su resolución dentro del marco puramente práctico suele hacerse mediante una simple recurrencia. Para este tipo de problemas hemos intentado conjugar las técnicas recurrentes usadas en economía con un planteamiento desde el punto de vista de las ecuaciones en diferencias. Matemáticamente, este texto es autocontenido y para su total comprensión solo son necesarias algunas nociones básicas de álgebra lineal. Para ello se ha abordado el desarrollo teórico introduciendo demostraciones sencillas y la menor cantidad posible de notaciones. Las demostraciones están insertadas tras cada enunciado. Solo las pruebas de la proposición 2.3.3 y del teorema 2.3.4 las incluimos en el apéndice B por su tecnicismo. En el apéndice C damos una demostración alternativa del teorema 2.2.5 mediante el uso de las aplicaciones lineales. Los desarrollos que aquí se plantean se basan en textos matemáticos clásicos y en el desarrollo natural, para un matemático, de los distintos conceptos, estudiando primero las propiedades de los objetos y después sus técnicas de cálculo. Introducimos el uso del ordenador como una herramienta de resolución de problemas numéricos, así como un método para obtener las soluciones de una ecuación en diferencias con coeficientes no necesariamente numéricos. Una vez conocidas las técnicas que planteamos de resolución de las ecuaciones en diferencias, podemos emplear el ordenador, que aplicará dichas técnicas para ahorrarnos el tedioso trabajo manual. El software que empleamos en este libro es MapleV, un conocido programa de cálculo simbólico comercial

Humoral and cellular immunity to SARS-COV-2 after vaccination with mRNA vaccines in PLWH with discordant immune response. Influence of the vaccine administered

Background: Data on SARS-CoV-2 mRNA vaccine immunogenicity in people living with human immunodeficiency virus (PLWH) and discordant immune response (DIR) are currently limited. Therefore, we compare the immunogenicity of these vaccines in DIR and immunological responders (IR). Methods: A prospective cohort that enrolled 89 participants. Finally, 22 IR and 24 DIR were analyzed before vaccination (T), one (T) and six months (T) after receiving BNT162b2 or mRNA-1273 vaccine. Additionally, 10 IR and 16 DIR were evaluated after a third dose (T). Anti-S-RBD IgG, neutralizing antibodies (nAb), neutralization activity, and specific memory B cells were quantified. Furthermore, specific CD4 and CD8 responses were determined by intracellular cytokine staining and polyfunctionality indexes (Pindex). Results: At T, all participants developed anti-S-RBD. 100% IR developed nAb compared to 83.3% DIR. Spike-specific B cells were detected in all IR and 21/24 DIR. Memory CD4 T cells responded in 5/9 IR and 7/9 DIR, mainly based on the expression of IFN-γ and TNF-α, with a higher Pindex in DIR. Memory CD8 T cells responded in only four participants in each group. At T, anti-S-RBD and nAb titers were higher in DIR than in IR. In both groups, there was an increase in specific B memory cells, higher in DIR. Six IR and five DIR maintained a specific memory CD4 response. Memory CD8 response was preserved in IR but was lost in DIR. In a multivariate linear regression analysis, receiving mRNA-1273 instead of BNT162b2 played a prominent role in the results. Conclusions: Our data suggest that PLWH with DIR can mount an immune response similar to those with higher CD4, provided they receive the mRNA-1273 vaccine instead of others less immunogenic.In collaboration with the Gilead Biomedical Research Grants Program GLD21_00096. In addition, this work was supported by Instituto de Salud Carlos III, co-financed by the European Regional Development Fund “a way to make Europe” through the Program Miguel Servet to AG-V (CP19/00159), PFIS contract to AS-A (FI21/ 00165) and EM-M (FI19/00304) and programa Rio Hortega to MM-T (CM21/00115). Consejerı́a de Transformación Económica, Industria, Conocimiento y Universidades, Junta de Andalucı́a, grant P20_00906

DataSheet_2_IP-10 and MIG are sensitive markers of early virological response to HIV-1 integrase inhibitors.docx

Supplementary Data Sheet 2 | Centres and investigators involved in CoRIS.[Background] Interferon-inducible protein-10 (IP-10) and monokine induced by interferon-gamma (MIG) are chemokines recognized as inflammatory biomarkers during HIV-1 infection. We assessed their early and long-term dynamics after initiation of antiretroviral treatment (ART).[Methods] Persons with HIV-1 (PWH) aged>18 years starting their first ART in 2015-2021 in a prospective cohort (n=73) were included. IP-10 and MIG plasma levels were quantified using a multiplexed bead-based assay.[Results] IP-10 and MIG plasma levels showed a significant and consistent reduction following ART (80% integrase inhibitor [INSTI]-based) initiation, starting at day 20 and maintained throughout the study period (48 months), paralleling the HIV-1 RNA decay and CD4+ count recovery (p<0·001). At baseline, PWH≥ 50 years, CDC stage C and CD4+ count<350cells/mm3 had higher levels of IP-10 (p=0·022, p=0·001 and p=0·002, respectively) and MIG (p<0·001, p=0·024 and p=0·069, respectively). All of them matched their counterparts several months following ART initiation. MIG levels showed a greater decrease at day 10 in those treated with INSTI (p=0·038). Low-level HIV-1 viremia did not impact MIG or IP-10 levels.[Conclusion] Plasma IP-10 and MIG showed an early significant decline following ART initiation, with greater early declines in MIG levels in INSTI-based regimens. These findings suggest a strong impact of HIV-1 viremia on IP-10 and MIG levels.Peer reviewe

IP-10 and MIG are sensitive markers of early virological response to HIV-1 integrase inhibitors

© 2023 Álvarez, Gutiérrez-Valencia, Mariño, Saborido-Alconchel, Calderón-Cruz, Pérez-González, Alonso-Domínguez, Martínez-Barros, Gallego-Rodríguez, Moreno, Aldamiz, Montero-Alonso, Bernal, Galera, Llibre and Poveda. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.Background: Interferon-inducible protein-10 (IP-10) and monokine induced by interferon-gamma (MIG) are chemokines recognized as inflammatory biomarkers during HIV-1 infection. We assessed their early and long-term dynamics after initiation of antiretroviral treatment (ART).Methods: Persons with HIV-1 (PWH) aged>18 years starting their first ART in 2015-2021 in a prospective cohort (n=73) were included. IP-10 and MIG plasma levels were quantified using a multiplexed bead-based assay.Results: IP-10 and MIG plasma levels showed a significant and consistent reduction following ART (80% integrase inhibitor [INSTI]-based) initiation, starting at day 20 and maintained throughout the study period (48 months), paralleling the HIV-1 RNA decay and CD4+ count recovery (p<0·001). At baseline, PWH≥ 50 years, CDC stage C and CD4+ count<350cells/mm3 had higher levels of IP-10 (p=0·022, p=0·001 and p=0·002, respectively) and MIG (p<0·001, p=0·024 and p=0·069, respectively). All of them matched their counterparts several months following ART initiation. MIG levels showed a greater decrease at day 10 in those treated with INSTI (p=0·038). Low-level HIV-1 viremia did not impact MIG or IP-10 levels.Conclusion: Plasma IP-10 and MIG showed an early significant decline following ART initiation, with greater early declines in MIG levels in INSTI-based regimens. These findings suggest a strong impact of HIV-1 viremia on IP-10 and MIG levels.The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This study has been funded by Instituto de Salud Carlos III [PI16/02159, BA18/00034, PI19/00747, PI22/01341, CM20/00243] and cofunded by the European Regional Development Fund, “A way to make Europe”; Red Española de Investigación en SIDA; Xunta de Galicia-Axencia Galega de Innovación (IN606A-2022/019); INVESTIGO Next GenerationEU Program TR349V-2022-10000052-00; Intramural Grant Program Galicia Sur Health Research Institute (CI22-A-2).Peer reviewe

It is time to define an organizational model for the prevention and management of infections along the surgical pathway: a worldwide cross-sectional survey

Background The objectives of the study were to investigate the organizational characteristics of acute care facilities worldwide in preventing and managing infections in surgery; assess participants' perception regarding infection prevention and control (IPC) measures, antibiotic prescribing practices, and source control; describe awareness about the global burden of antimicrobial resistance (AMR) and IPC measures; and determine the role of the Coronavirus Disease 2019 pandemic on said awareness. Methods A cross-sectional web-based survey was conducted contacting 1432 health care workers (HCWs) belonging to a mailing list provided by the Global Alliance for Infections in Surgery. The self-administered questionnaire was developed by a multidisciplinary team. The survey was open from May 22, 2021, and June 22, 2021. Three reminders were sent, after 7, 14, and 21 days. Results Three hundred four respondents from 72 countries returned a questionnaire, with an overall response rate of 21.2%. Respectively, 90.4% and 68.8% of participants stated their hospital had a multidisciplinary IPC team or a multidisciplinary antimicrobial stewardship team. Local protocols for antimicrobial therapy of surgical infections and protocols for surgical antibiotic prophylaxis were present in 76.6% and 90.8% of hospitals, respectively. In 23.4% and 24.0% of hospitals no surveillance systems for surgical site infections and no monitoring systems of used antimicrobials were implemented. Patient and family involvement in IPC management was considered to be slightly or not important in their hospital by the majority of respondents (65.1%). Awareness of the global burden of AMR among HCWs was considered very important or important by 54.6% of participants. The COVID-19 pandemic was considered by 80.3% of respondents as a very important or important factor in raising HCWs awareness of the IPC programs in their hospital. Based on the survey results, the authors developed 15 statements for several questions regarding the prevention and management of infections in surgery. The statements may be the starting point for designing future evidence-based recommendations. Conclusion Adequacy of prevention and management of infections in acute care facilities depends on HCWs behaviours and on the organizational characteristics of acute health care facilities to support best practices and promote behavioural change. Patient involvement in the implementation of IPC is still little considered. A debate on how operationalising a fundamental change to IPC, from being solely the HCWs responsibility to one that involves a collaborative relationship between HCWs and patients, should be opened

Evolving trends in the management of acute appendicitis during COVID-19 waves. The ACIE appy II study

Background: In 2020, ACIE Appy study showed that COVID-19 pandemic heavily affected the management of patients with acute appendicitis (AA) worldwide, with an increased rate of non-operative management (NOM) strategies and a trend toward open surgery due to concern of virus transmission by laparoscopy and controversial recommendations on this issue. The aim of this study was to survey again the same group of surgeons to assess if any difference in management attitudes of AA had occurred in the later stages of the outbreak. Methods: From August 15 to September 30, 2021, an online questionnaire was sent to all 709 participants of the ACIE Appy study. The questionnaire included questions on personal protective equipment (PPE), local policies and screening for SARS-CoV-2 infection, NOM, surgical approach and disease presentations in 2021. The results were compared with the results from the previous study. Results: A total of 476 answers were collected (response rate 67.1%). Screening policies were significatively improved with most patients screened regardless of symptoms (89.5% vs. 37.4%) with PCR and antigenic test as the preferred test (74.1% vs. 26.3%). More patients tested positive before surgery and commercial systems were the preferred ones to filter smoke plumes during laparoscopy. Laparoscopic appendicectomy was the first option in the treatment of AA, with a declined use of NOM. Conclusion: Management of AA has improved in the last waves of pandemic. Increased evidence regarding SARS-COV-2 infection along with a timely healthcare systems response has been translated into tailored attitudes and a better care for patients with AA worldwide

Correction to: Two years later: Is the SARS-CoV-2 pandemic still having an impact on emergency surgery? An international cross-sectional survey among WSES members

Background: The SARS-CoV-2 pandemic is still ongoing and a major challenge for health care services worldwide. In the first WSES COVID-19 emergency surgery survey, a strong negative impact on emergency surgery (ES) had been described already early in the pandemic situation. However, the knowledge is limited about current effects of the pandemic on patient flow through emergency rooms, daily routine and decision making in ES as well as their changes over time during the last two pandemic years. This second WSES COVID-19 emergency surgery survey investigates the impact of the SARS-CoV-2 pandemic on ES during the course of the pandemic. Methods: A web survey had been distributed to medical specialists in ES during a four-week period from January 2022, investigating the impact of the pandemic on patients and septic diseases both requiring ES, structural problems due to the pandemic and time-to-intervention in ES routine. Results: 367 collaborators from 59 countries responded to the survey. The majority indicated that the pandemic still significantly impacts on treatment and outcome of surgical emergency patients (83.1% and 78.5%, respectively). As reasons, the collaborators reported decreased case load in ES (44.7%), but patients presenting with more prolonged and severe diseases, especially concerning perforated appendicitis (62.1%) and diverticulitis (57.5%). Otherwise, approximately 50% of the participants still observe a delay in time-to-intervention in ES compared with the situation before the pandemic. Relevant causes leading to enlarged time-to-intervention in ES during the pandemic are persistent problems with in-hospital logistics, lacks in medical staff as well as operating room and intensive care capacities during the pandemic. This leads not only to the need for triage or transferring of ES patients to other hospitals, reported by 64.0% and 48.8% of the collaborators, respectively, but also to paradigm shifts in treatment modalities to non-operative approaches reported by 67.3% of the participants, especially in uncomplicated appendicitis, cholecystitis and multiple-recurrent diverticulitis. Conclusions: The SARS-CoV-2 pandemic still significantly impacts on care and outcome of patients in ES. Well-known problems with in-hospital logistics are not sufficiently resolved by now; however, medical staff shortages and reduced capacities have been dramatically aggravated over last two pandemic years

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

DataSheet_1_IP-10 and MIG are sensitive markers of early virological response to HIV-1 integrase inhibitors.zip

Supplementary Figure S1 | Dynamic changes in IP-10 plasma levels and CD4+ T-cell (A); dynamic changes in IP-10 plasma levels and HIV-1 RNA (B); dynamic changes in MIG plasma levels and CD4+ T-cell (C); dynamic changes in MIG plasma levels and HIV-1 RNA (D), throughout 12 months after ART initiation. IP-10, Interferon-inducible protein 10; MIG, Monokine induced by interferon-gamma; ART, antiretroviral treatment; M6, month 6; M12, month 12. Global tendency (throughout all time points represented in graph) p value, calculated with the Friedman Test. IP-10, MIG, CD4+ T-cell count and HIV-1 RNA plasma levels are represented as plasma concentrations median values.-- Supplementary Figure S2 | Correlation between IP-10 plasma levels and CD4+ T-cell count (A) and correlation between IP-10 plasma levels and HIV-1 RNA (B), throughout 12 months after ART initiation. IP-10, Interferon-inducible protein-10; ART, antiretroviral treatment; r, correlation coefficient Spearman. Statistically significant values of variables are highlighted in bold.-- Supplementary Figure S3 | Correlation between MIG plasma levels and CD4+ T-cell count (A) and correlation between MIG plasma levels and HIV-1 RNA (B), throughout 12 months after ART initiation. MIG, Monokine induced by interferon-gamma; ART, antiretroviral treatment; r, correlation coefficient Spearman. Statistically significant values of variables are highlighted in bold.-- Supplementary Figure S4 | Correlation between IP-10 plasma levels and CD4+ T-cell count (A) and correlation between IP-10 plasma levels and HIV-1 RNA (B), throughout early time points after ART initiation. IP-10, Interferon-inducible protein-10; ART, antiretroviral treatment; r, correlation coefficient Spearman. Statistically significant values of variables are highlighted in bold.-- Supplementary Figure S5 | Correlation between MIG plasma levels and CD4+ T-cell count (A) and correlation between MIG plasma levels and HIV-1 RNA (B), throughout early time points after ART initiation. MIG, Monokine induced by interferon-gamma; ART, antiretroviral treatment; r, correlation coefficient Spearman. Statistically significant values of variables are highlighted in bold.-- Supplementary Table S1 | Dynamic changes in CD4+ T-cell count and HIV-1 RNA after ART initiation overall (throughout 12 months) (A). Dynamic changes in CD4+ T-cell count and HIV-1 RNA after ART initiation throughout early time points (B). ART, antiretroviral treatment; D10, day 10; D20, day 20; M1, month 1; M3, month 3; M6, month 6; M12, month 12; IQR, interquartile range. Statistically significant values of variables are highlighted in bold.-- Supplementary Table S2 | Impact of low-level viremia, target detected or target not detected below 20 copies/mL on IP-10 and MIG plasma levels, 12 months after ART initiation. IP-10, Interferon-inducible protein-10; MIG, Monokine induced by interferon-gamma; M12, month 12; n, number of individuals. Statistically significant values of variables are highlighted in bold. * Low-level viremia is defined as HIV-1 RNA 20-199copies/mL.[Background] Interferon-inducible protein-10 (IP-10) and monokine induced by interferon-gamma (MIG) are chemokines recognized as inflammatory biomarkers during HIV-1 infection. We assessed their early and long-term dynamics after initiation of antiretroviral treatment (ART).[Methods] Persons with HIV-1 (PWH) aged>18 years starting their first ART in 2015-2021 in a prospective cohort (n=73) were included. IP-10 and MIG plasma levels were quantified using a multiplexed bead-based assay.[Results] IP-10 and MIG plasma levels showed a significant and consistent reduction following ART (80% integrase inhibitor [INSTI]-based) initiation, starting at day 20 and maintained throughout the study period (48 months), paralleling the HIV-1 RNA decay and CD4+ count recovery (p<0·001). At baseline, PWH≥ 50 years, CDC stage C and CD4+ count<350cells/mm3 had higher levels of IP-10 (p=0·022, p=0·001 and p=0·002, respectively) and MIG (p<0·001, p=0·024 and p=0·069, respectively). All of them matched their counterparts several months following ART initiation. MIG levels showed a greater decrease at day 10 in those treated with INSTI (p=0·038). Low-level HIV-1 viremia did not impact MIG or IP-10 levels.[Conclusion] Plasma IP-10 and MIG showed an early significant decline following ART initiation, with greater early declines in MIG levels in INSTI-based regimens. These findings suggest a strong impact of HIV-1 viremia on IP-10 and MIG levels.Peer reviewe