12 research outputs found
About ghost transients in spatial continuous media
Altres ajuts: acords transformatius de la UABThe impact of space on ecosystem dynamics has been a matter of debate since the dawn of theoretical ecology. Several studies have revealed that space usually involves an increase in transients' times, promoting the so-called supertransients. However, the effect of space and diffusion in transients close to bifurcations has not been thoroughly investigated. In non-spatial deterministic models such as those given by ordinary differential equations transients become extremely long in the vicinity of bifurcations. Specifically, for the saddle-node (s-n) bifurcation the time delay, τ, follows τ∼|μ−μ|; μ and μ being the bifurcation parameter and the bifurcation value, respectively. Such long transients are labeled delayed transitions and are governed by the so-called ghosts. Here, we explore a simple model with intra-specific cooperation (autocatalysis) and habitat loss undergoing a s-n bifurcation using a partial differential equations (PDE) approach. We focus on the effects of diffusion in the ghost extinction transients right after the tipping point found at a critical habitat loss threshold. Our results show that the bifurcation value does not depend on diffusion. Despite transients' length typically increase close to the bifurcation, we have observed that at extreme values of diffusion, both small and large, extinction times remain long and close to the well-mixed results. However, ghosts lose influence at intermediate diffusion rates, leading to a dramatic reduction of transients' length. These results, which strongly depend on the initial size of the population, are shown to remain robust for different initial spatial distributions of cooperators. A simple two-patch metapopulation model gathering the main results obtained from the PDEs approach is also introduced and discussed. Finally, we provide analytical results of the passage times and the scaling for the model under study transformed into a normal form. Our findings are discussed within the framework of ecological transients
On the basic reproduction number in continuously structured populations
In the framework of population dynamics, the basic reproduction number (Formula presented.) is, by definition, the expected number of offspring that an individual has during its lifetime. In constant and time periodic environments, it is calculated as the spectral radius of the so-called next-generation operator. In continuously structured populations defined in a Banach lattice X with concentrated states at birth, one cannot define the next-generation operator in X. In the present paper, we present an approach to compute the basic reproduction number of such models as the limit of the basic reproduction number of a sequence of models for which (Formula presented.) can be computed as the spectral radius of the next-generation operator. We apply these results to some examples: the (classical) size-dependent model, a size-structured cell population model, a size-structured model with diffusion in structure space (under some particular assumptions), and a (physiological) age-structured model with diffusion in structure space
La càrrega futura de l'excés de casos de diabetis mellitus de tipus 1 durant la pandèmia de COVID a Catalunya: avaluació econòmica
Diabetis mellitus de tipus 1; COVID-19; Avaluació econòmicaDiabetes mellitus de tipo 1; COVID-19; Evaluación económicaType 1 diabetes mellitus; COVID-19; Economic evaluationThis paper aims to provide a comprehensive assessment of the impact of the excess cases
of DM1 during the first two years of the COVID-19 pandemic on health outcomes and health
spending in Catalonia.Este documento pretende proporcionar una evaluación exhaustiva del impacto del exceso
de casos de DM1 durante los dos primeros años de la pandemia COVID-19 en resultados de
salud y gasto sanitario en Cataluña.Aquest document pretén proporcionar una avaluació exhaustiva de l'impacte de l'excés de
casos de DM1 durant els dos primers anys de la pandèmia COVID-19 en els resultats de
salut i la despesa sanitària a Catalunya
Telehealth model versus in-person standard care for persons with type 1 diabetes treated with multiple daily injections: an open-label randomized controlled trial
ObjectiveIncreasing evidence indicates that the telehealth (TH) model is noninferior to the in-person approach regarding metabolic control in type 1 diabetes (T1D) and offers advantages such as a decrease in travel time and increased accessibility for shorter/frequent visits. The primary aim of this study was to compare the change in glycated hemoglobin (HbA1c) at 6 months in T1D care in a rural area between TH and in-person visits.Research design and methodsRandomized controlled, open-label, parallel-arm study among adults with T1D. Participants were submitted to in-person visits at baseline and at months 3 and 6 (conventional group) or teleconsultation in months 1 to 4 plus 2 in-person visits (baseline and 6 months) (TH group). Mixed effects models estimated differences in HbA1c changes.ResultsFifty-five participants were included (29 conventional/26 TH). No significant differences in HbA1c between groups were found. Significant improvement in time in range (5.40, 95% confidence interval (CI): 0.43-10.38; p < 0.05) and in time above range (-6.34, 95% CI: -12.13- -0.55;p < 0.05) in the TH group and an improvement in the Diabetes Quality of Life questionnaire (EsDQoL) score (-7.65, 95% CI: -14.67 - -0.63; p < 0.05) were observed. In TH, the costs for the participants were lower.ConclusionsThe TH model is comparable to in-person visits regarding HbA1c levels at the 6-month follow-up, with significant improvement in some glucose metrics and health-related quality of life. Further studies are necessary to evaluate a more efficient timing of the TH visits
Reference Intervals of Thyroid Function Tests Assessed by Immunoassay and Mass Spectrometry in Healthy Pregnant Women Living in Catalonia
Background: Recent guidelines recommend establishing a local reference interval (RI) for thyroid function. We aimed to establish trimester-specific RIs for thyrotropin (TSH) and free thyroxine (FT4) in a cohort of healthy pregnant women in Catalonia (Spain). Methods: A prospective observational study was conducted with 332 healthy pregnant women, from the first trimester (1T) to delivery. TSH was measured using an Architect ® immunoassay (Abbott) and FT4 by two immunoassays, Architect ® (Abbott) and Cobas ® (Roche), in the three trimesters. FT4 was also measured by liquid chromatography mass spectrometry (LC/MS/MS) in the 1T. Results: TSH (µUI/mL) increased throughout pregnancy (1T: 0.03-3.78; 2T: 0.51-3.53; 3T: 0.50-4.32; p < 0.0001) and FT4 (pmol/L) progressively decreased (Architect ® 1T: 10.42-15.96; 2T: 8.37-12.74; 3T: 8.24-12.49; p < 0.0001; and Cobas ® : 1T: 11.46-19.05; 2T: 9.65-14.67; 3T: 8.88-14.54; p < 0.0067). The FT4 RI during 1T determined LC/MS/MS was 8.75-18.27. Despite the 1T FT4 results measured by LC/MS/MS and with the two immunoassays being significantly correlated, the results obtained by the three methods were found to be non-interchangeable. Conclusions: We established trimester-specific RIs for TSH and for FT4 with immunoassays in our population. We also validated the 1T FT4 using LC/MS/MS to confirm the results of FT4 lower than the 2.5th percentile or higher than the 97.5th percentile
Abdominal obesity and dsyglycemia are risk factors for liver fibrosis progression in NAFLD subjects : A population-based study
To investigate longitudinal changes in the liver stiffness measurement (LSM) in the general adult population without known liver disease and to describe its association with metabolic risk factors, with a special focus on subjects with non-alcoholic fatty liver disease (NAFLD) and dysglycemia. A longitudinal adult population-based cohort study was conducted in Catalonia. LSM was measured by transient elastography (TE) at baseline and follow-up (median: 4.2 years). Subgroup with NAFLD and dysglycemia were analyzed. Moderate-to-advanced liver fibrosis was defined as LSM ≥8.0 kPa and LSM ≥9.2 kPa respectively. Among 1.478 subjects evaluated, the cumulative incidence of LSM ≥8.0 kPa and ≥9.2 kPa at follow-up was 2.8% and 1.9%, respectively. This incidence was higher in NAFLD (7.1% for LSM ≥8.0 kPa and 5% for LSM ≥9.2 kPa) and dysglycemia (6.2% for LSM ≥8.0 kPa and 4.7% for LSM ≥9.2 kPa) subgroups. In the global cohort, the multivariate analyses showed that dysglycemia, abdominal obesity and atherogenic dyslipidemia were significantly associated with progression to moderate-to-advanced liver fibrosis. Female sex was negatively associated. In subjects with NAFLD, abdominal obesity and dysglycemia were associated with changes in LSM to ≥8.0 kPa and ≥9.2 kPa at follow-up. A decline in LSM value to <8 kPa was observed in 64% of those subjects with a baseline LSM ≥8.0 kPa. In this population study, the presence of abdominal obesity and dysglycemia were the main risk metabolic factors associated with moderate-to-advanced liver fibrosis development over time in general populations as well as in subjects with NAFLD
Nutrición parenteral domiciliaria en España, 2019: informe del Grupo de Nutrición Artificial Domiciliaria y Ambulatoria NADYA
RESUMEN Objetivo: comunicar los datos de nutrición parenteral domiciliaria (NPD) obtenidos del registro del grupo NADYA-SENPE (www.nadyasenpe.com) del año 2019. Material y métodos: análisis descriptivo de los datos recogidos de pacientes adultos y pediátricos con NPD en el registro NADYA-SENPE desde el 1 de enero al 31 de diciembre de 2019. Resultados: se registraron 283 pacientes (51,9 %, mujeres), 31 niños y 252 adultos procedentes de 47 hospitales españoles, lo que representa una tasa de prevalencia de 6,01 pacientes/millón de habitantes/año 2019. El diagnóstico más frecuente en los adultos fue “oncológico paliativo” y “otros” (21,0 %). En los niños fue la enfermedad de Hirschsprung junto a la enterocolitis necrotizante, las alteraciones de la motilidad intestinal y la pseudoobstrucción intestinal crónica, con 4 casos cada uno (12,9 %). El primer motivo de indicación fue el síndrome del intestino corto tanto en los niños (51,6 %) como en los adultos (37,3 %). El tipo de catéter más utilizado fue el tunelizado tanto en los niños (75,9 %) como en los adultos (40,8 %). Finalizaron 68 episodios, todos en adultos: la causa más frecuente fue el fallecimiento (54,4 %). Pasaron a la vía oral el 38,2 %. Conclusiones: el número de centros y profesionales colaboradores con el registro NADYA va incrementándose. Se mantienen estables las principales indicaciones y los motivos de finalización de la NPD
Viabilidad de los índices antropométricos de adiposidad basados en el peso (body weight - related) y los índices basados en la forma (body shape - related) en la predicción del síndrome metabólico y de la enfermedad cardiovascular en población adulta
Evaluar la viabilidad de distintos índices antropométricos de adiposidad en la predicción de factores de riesgo cardiovascular, síndrome metabólico y enfermedad cardiovascular en una muestra de población adulta heterogénea.To evaluate the viability of different anthropometric adiposity indices in the prediction of cardiovascular risk factors, metabolic syndrome and cardiovascular disease in a heterogeneous sample of adult population.Avaluar la viabilitat de diferents índexs antropomètrics d'adipositat en la predicció de factors de risc cardiovascular, síndrome metabòlica i malaltia cardiovascular en una mostra de població adulta heterogènia
Reliability of a computer-aided system in the evaluation of indeterminate ultrasound images of thyroid nodules
Computer-aided diagnostic (CAD) programs for malignancy risk stratification from ultrasound (US) imaging of thyroid nodules are being validated both experimentally and in real-world practice. However, they have not been tested for reliability in analyzing difficult or unclear images. US images with indeterminate characteristics were evaluated by five observers with different experience in US examination and by a commercial CAD program. The nodules, on which the observers widely agreed, were considered concordant and, if there was little agreement, not concordant or difficult to assess. The diagnostic performance of the readers and the CAD program was calculated and compared in both groups of nodule images. In the group of concordant thyroid nodules (n = 37), the clinicians and the CAD system obtained similar levels of accuracy (77.0% vs 74.2%, respectively; P = 0.7) and no differences were found in sensitivity (SEN) (95.0% vs 87.5%, P = 0.2), specificity (SPE) (45.5 vs 49.4, respectively; P = 0.7), positive predictive value (PPV) (75.2% vs 77.7%, respectively; P = 0.8), nor negative predictive value (NPV) (85.6 vs 77.7, respectively; P = 0.3). When analyzing the non-concordant nodules (n = 43), the CAD system presented a decrease in accuracy of 4.2%, which was significantly lower than that observed by the experts (19.9%, P = 0.02). Clinical observers are similar to the CAD system in the US assessment of the risk of thyroid nodules. However, the AI system for thyroid nodules AmCAD-UT ® showed more reliability in the analysis of unclear or misleading images
Telehealth model versus in-person standard care for persons with type 1 diabetes treated with multiple daily injections : an open-label randomized controlled trial
Increasing evidence indicates that the telehealth (TH) model is noninferior to the in-person approach regarding metabolic control in type 1 diabetes (T1D) and offers advantages such as a decrease in travel time and increased accessibility for shorter/frequent visits. The primary aim of this study was to compare the change in glycated hemoglobin (HbA) at 6 months in T1D care in a rural area between TH and in-person visits. Randomized controlled, open-label, parallel-arm study among adults with T1D. Participants were submitted to in-person visits at baseline and at months 3 and 6 (conventional group) or teleconsultation in months 1 to 4 plus 2 in-person visits (baseline and 6 months) (TH group). Mixed effects models estimated differences in HbA changes. Fifty-five participants were included (29 conventional/26 TH). No significant differences in HbA between groups were found. Significant improvement in time in range (5.40, 95% confidence interval (CI): 0.43-10.38; p < 0.05) and in time above range (-6.34, 95% CI: -12.13- -0.55;p < 0.05) in the TH group and an improvement in the Diabetes Quality of Life questionnaire (EsDQoL) score (-7.65, 95% CI: -14.67 - -0.63; p < 0.05) were observed. In TH, the costs for the participants were lower. The TH model is comparable to in-person visits regarding HbA levels at the 6-month follow-up, with significant improvement in some glucose metrics and health-related quality of life. Further studies are necessary to evaluate a more efficient timing of the TH visits