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Mathematical models are among the most successful strategies for predicting the dynamics of a disease spreading in a population. Among them, the so-called compartmental models, where the total population is proportionally divided into compartments, are widely used. The SIR model (Susceptible-Infected-Recovered) is one of them, where the dynamics between the compartments follows a system of nonlinear differential equations. As a result of the non-linearity of the SIR dynamics, it has no analytical solution. Therefore, some numerical methods must be used to obtain an approximate solution. In this contribution, we present simulated scenarios for the SIR model showing its stiffness, a phenomenon that implies the necessity of a small step size choice in the numerical approximation. The numerical results, in particular, show that the stiffness phenomenon increases with higher transmission rates and lower birth and mortality rates . We compare the numerical solutions and errors for the SIR model using explicit Euler, Runge Kutta, and the semi-implicit Rosenbrock methods and analyze the numerical implications of the stiffness on them. As a result, we conclude that any accurate numerical solution of the SIR model will depend on an appropriately chosen numerical method and the time step, in terms of the values of the parameters.

Em um contexto em que se promove o uso de metodologias ativas, estratégias e planejamentos de aulas aliados à tecnologia, entre outras muitas ferramentas tão significativas para disponibilizar um ambiente propício ao desenvolvimento de um aprendizado eficaz, questiona-se por que nossos alunos não alcançam os objetivos propostos. O que é necessário de fato para que o processo de ensino/aprendizagem seja eficaz e torne o aluno um indivíduo autônomo? O problema talvez não esteja somente no aluno. Será que o professor, mesmo tendo capacitação profissional para atuar na sua área, teve as orientações e a formação acadêmica necessária para trazer aos alunos métodos e ferramentas para as mais amplas possibilidades de melhorarem seu universo do conhecimento? Nesse contexto, esse trabalho tem o objetivo de trazer uma reflexão sobre a formação docente de maneira a atender a demanda no contexto atual da educação, somado ao ato pedagógico que incentive no professor a autonomia que muitas vezes ele deve instigar em seus alunos, mas devido à falta de motivação e atuação do “ser professor” não consegue desenvolver as habilidades que a educação exige.

Background: Medically unexplained symptoms otherwise referred to as persistent physical symptoms (PPS) are debilitating to patients. As many specific PPS syndromes share common behavioural, cognitive, and affective influences, transdiagnostic treatments might be effective for this patient group. We evaluated the clinical efficacy and cost-effectiveness of a therapist-delivered, transdiagnostic cognitive behavioural intervention (TDT-CBT) plus (+) standard medical care (SMC) v. SMC alone for the treatment of patients with PPS in secondary medical care. Methods: A two-arm randomised controlled trial, with measurements taken at baseline and at 9, 20, 40- and 52-weeks post randomisation. The primary outcome measure was the Work and Social Adjustment Scale (WSAS) at 52 weeks. Secondary outcomes included mood (PHQ-9 and GAD-7), symptom severity (PHQ-15), global measure of change (CGI), and the Persistent Physical Symptoms Questionnaire (PPSQ). Results: We randomised 324 patients and 74% were followed up at 52 weeks. The difference between groups was not statistically significant for the primary outcome (WSAS at 52 weeks: estimated difference −1.48 points, 95% confidence interval from −3.44 to 0.48, p = 0.139). However, the results indicated that some secondary outcomes had a treatment effect in favour of TDT-CBT + SMC with three outcomes showing a statistically significant difference between groups. These were WSAS at 20 weeks (p = 0.016) at the end of treatment and the PHQ-15 (p = 0.013) and CGI at 52 weeks (p = 0.011). Conclusion: We have preliminary evidence that TDT-CBT + SMC may be helpful for people with a range of PPS. However, further study is required to maximise or maintain effects seen at end of treatment. [ABSTRACT FROM AUTHOR]

The influence of environmental insults on the onset and progression of mitochondrial diseases is unknown. To evaluate the effects of infection on mitochondrial disease we used a mouse model of Leigh Syndrome, where a missense mutation in the Taco1 gene results in the loss of the translation activator of cytochrome c oxidase subunit I (TACO1) protein. The mutation leads to an isolated complex IV deficiency that mimics the disease pathology observed in human patients with TACO1 mutations. We infected Taco1 mutant and wild-type mice with a murine cytomegalovirus and show that a common viral infection exacerbates the complex IV deficiency in a tissue-specific manner. We identified changes in neuromuscular morphology and tissue-specific regulation of the mammalian target of rapamycin pathway in response to viral infection. Taken together, we report for the first time that a common stress condition, such as viral infection, can exacerbate mitochondrial dysfunction in a genetic model of mitochondrial disease. Author summary: Mitochondrial diseases are the most commonly inherited metabolic disorders that are heterogenic and have varied disease onset and progression. Acquired infections and the associated inflammatory responses are known triggers for mitochondrial disease in the clinic and can cause progressive deterioration in patients with mitochondrial disease. Knowledge of how an infection causes and contributes to the progression of mitochondrial disease is completely lacking and has never before been investigated. Here we examined the effects of a viral infection in a model of energy dysfunction and identified that cytomegalovirus can worsen the progression of mitochondrial disease symptoms. [ABSTRACT FROM AUTHOR]

Introduction Persistent physical symptoms (PPS), also known as medically unexplained symptoms are associated with profound physical disability, psychological distress and high healthcare costs. England's annual National Health Service costs of attempting to diagnose and treat PPS amounts to approximately £3 billion. Current treatment relies on a positive diagnosis, life-style advice and drug therapy. However, many patients continue to suffer from ongoing symptoms and general practitioners (GPs) are challenged to find effective treatments. Training GPs in basic cognitive behavioural skills and providing self-help materials to patients could be useful, but availability in primary care settings is limited. Methods and analysis A cluster randomised waiting list, controlled trial will be conducted to assess the feasibility of an integrated approach to care in general practice. Approximately 240 patients with PPS will be recruited from 8 to 12 GP practices in London. GP practices will be randomised to 'integrated GP care plus treatment as usual' or waiting list control. Integrated GP care plus treatment as usual will include GP training in cognitive behavioural skills, GP supervision and written and audio visual materials for both GPs and participants. The primary objectives will be assessment of trial and intervention feasibility. Secondary objectives will include estimating the intracluster correlation coefficient for potential outcome measures for cluster effects in a sample size calculation. Feasibility parameters and identification of suitable primary and secondary outcomes for future trial evaluations will be assessed prerandomisation and at 12 and 24 weeks' postrandomisation, using a mixed-methods approach. Ethics and dissemination Ethical approval was granted by the Camberwell St Giles Ethics Committee. Results will be disseminated via peer-reviewed publications and conference presentations. This trial will inform researchers, clinicians, patients and healthcare providers about the feasibility and potential cost-effectiveness of an integrated approach to managing PPS in primary care. [ABSTRACT FROM AUTHOR]

Repeat proteins regulate the expression of the mammalian mitochondrial genome at the level of transcription, processing, maturation, and translation. Defects in the regulation of mitochondrial gene expression due to mutations in genes encoding repeat proteins can lead to mitochondrial dysfunction and disease, however the molecular mechanisms that regulate mitochondrial gene expression and how defects in these processes cause disease still remains poorly understood. Recently solved crystal structures, characterisation of the new genetic models, and use of RNA sequencing (RNA-Seq) technologies have greatly expanded our current understanding of mitochondrial repeat proteins and biology. [ABSTRACT FROM AUTHOR]

Objective: To contribute to an optimised training programme for care staff that supports the implementation of evidence-based psychosocial interventions in long-term care.Methods: Qualitative study that involved focus group discussions with 119 care home staff within 16 care homes in the UK. Part of wider clinical trial aimed at developing and evaluating an effective and practical psychosocial intervention and implementation approach for people with dementia in long-term care. Inductive thematic analysis was used to identify themes and interpret the data.Results: The findings highlighted that successful training and support interventions must acknowledge and respond to 'whole home' issues. Three overarching themes emerged as influential: the importance of contextual factors such as staff morale, interpersonal relationships within the home, and experience and perceived value of the proposed intervention.Conclusions: Priority must be given to obtain the commitment of all staff, management and relatives to the training programme and ensure that expectations regarding interaction with residents, participation in activities and the reduction of medication are shared across the care home. [ABSTRACT FROM AUTHOR]

Objectives Emerging literature suggests that lifestyle factors may play an important role in reducing age-related cognitive decline. There have, however, been few studies investigating the role of cognitively stimulating leisure activities in maintaining cognitive health. This study sought to identify changes in cognitive performance with age and to investigate associations of cognitive performance with several key cognitively stimulating leisure activities. Method Over 65,000 participants provided demographic and lifestyle information and completed tests of grammatical reasoning, spatial working memory, verbal working memory and episodic memory. Results Regression analyses suggested that frequency of engaging in Sudoku or similar puzzles was significantly positively associated with grammatical reasoning, spatial working memory and episodic memory scores. Furthermore, for participants aged under 65 years, frequency of playing non-cognitive training computer games was also positively associated with performance in the same cognitive domains. The results also suggest that grammatical reasoning and episodic memory are particularly vulnerable to age-related decline. Further investigation to determine the potential benefits of participating in Sudoku puzzles and non-cognitive computer games is indicated, particularly as they are associated with grammatical reasoning and episodic memory, cognitive domains found to be strongly associated with age-related cognitive decline. Conclusions Results of this study have implications for developing improved guidance for the public regarding the potential value of cognitively stimulating leisure activities. The results also suggest that grammatical reasoning and episodic memory should be targeted in developing appropriate outcome measures to assess efficacy of future interventions, and in developing cognitive training programmes to prevent or delay cognitive decline. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Background: Patients continue to suffer from medically unexplained symptoms otherwise referred to as persistent physical symptoms (PPS). General practitioners (GPs) play a key role in the management of PPS and require further training. Patients are often frustrated with the care they receive. This study aims to assess the acceptability of an 'integrated GP care' approach which consists of offering self-help materials to patients with PPS and offering their GPs training on how to utilise cognitive behavioural skills within their consultations, as well as assessing the feasibility of conducting a future trial in primary care to evaluate its benefit. Methods: A feasibility cluster randomised controlled trial was conducted in primary care, South London, UK. GP practices (clusters) were randomly allocated to 'integrated GP care plus treatment as usual' or 'treatment as usual'. Patients with PPS were recruited from participating GP practices before randomisation. Feasibility parameters, process variables and potential outcome measures were collected at pre-randomisation and at 12- and 24-weeks post-randomisation at cluster and individual participant level. Results: Two thousand nine hundred seventy-eight patients were identified from 18 GP practices. Out of the 424 patients who responded with interest in the study, 164 fully met the eligibility criteria. One hundred sixty-one patients provided baseline data before cluster randomisation and therefore were able to participate in the study. Most feasibility parameters indicated that the intervention was acceptable and a future trial feasible. 50 GPs from 8 GP practices (randomised to intervention) attended the offer of training and provided positive feedback. Scores in GP knowledge and confidence increased post-training. Follow-up rate of patients at 24 weeks was 87%. However estimated effect sizes on potential clinical outcomes were small. Conclusions: It was feasible to identify and recruit patients with PPS. Retention rates of participants up to 24 weeks were high. A wide range of health services were used. The intervention was relatively low cost and low risk. This complex intervention should be further developed to improve patients'/GPs' utilisation of audio/visual and training resources before proceeding to a full trial evaluation. Trial registration: NCT02444520 (ClinicalTrials.gov). [ABSTRACT FROM AUTHOR]

Translation fidelity is crucial for prokaryotes and eukaryotic nuclear‐encoded proteins; however, little is known about the role of mistranslation in mitochondria and its potential effects on metabolism. We generated yeast and mouse models with error‐prone and hyper‐accurate mitochondrial translation, and found that translation rate is more important than translational accuracy for cell function in mammals. Specifically, we found that mitochondrial mistranslation causes reduced overall mitochondrial translation and respiratory complex assembly rates. In mammals, this effect is compensated for by increased mitochondrial protein stability and upregulation of the citric acid cycle. Moreover, this induced mitochondrial stress signaling, which enables the recovery of mitochondrial translation via mitochondrial biogenesis, telomerase expression, and cell proliferation, and thereby normalizes metabolism. Conversely, we show that increased fidelity of mitochondrial translation reduces the rate of protein synthesis without eliciting a mitochondrial stress response. Consequently, the rate of translation cannot be recovered and this leads to dilated cardiomyopathy in mice. In summary, our findings reveal mammalian‐specific signaling pathways that respond to changes in the fidelity of mitochondrial protein synthesis and affect metabolism. Synopsis: Experimental manipulation of the fidelity of mitochondrial protein synthesis reveals that translation rate is more critical than translational accuracy. Error‐prone translation elicits stress responses to rescue energy metabolism, while increased fidelity cannot induce such a compensatory response. Mitochondrial mistranslation causes changes in mitochondrial metabolism in mouse liver that recover over time.Stress signalling enables recovery from mistranslation by stimulating cell proliferation and mitochondrial biogenesis.High‐fidelity translation reduces mitochondrial protein synthesis without eliciting a compensatory response, resulting in dilated cardiomyopathy. [ABSTRACT FROM AUTHOR]

The contribution of dysregulated mitochondrial gene expression and consequent imbalance in biogenesis is not well understood in metabolic disorders such as insulin resistance and obesity. The ribosomal RNA maturation protein PTCD1 is essential for mitochondrial protein synthesis and its reduction causes adult-onset obesity and liver steatosis. We used haploinsufficient Ptcd1 mice fed normal or high fat diets to understand how changes in mitochondrial biogenesis can lead to metabolic dysfunction. We show that Akt-stimulated reduction in lipid content and upregulation of mitochondrial biogenesis effectively protected mice with reduced mitochondrial protein synthesis from excessive weight gain on a high fat diet, resulting in improved glucose and insulin tolerance and reduced lipid accumulation in the liver. However, inflammation of the white adipose tissue and early signs of fibrosis in skeletal muscle, as a consequence of reduced protein synthesis, were exacerbated with the high fat diet. We identify that reduced mitochondrial protein synthesis and OXPHOS biogenesis can be recovered in a tissue-specific manner via Akt-mediated increase in insulin sensitivity and transcriptional activation of the mitochondrial stress response.

Mitochondrial gene expression is essential for energy production; however, an understanding of how it can influence physiology and metabolism is lacking. Several proteins from the pentatricopeptide repeat (PPR) family are essential for the regulation of mitochondrial gene expression, but the functions of the remaining members of this family are poorly understood. We created knockout mice to investigate the role of the PPR domain 1 (PTCD1) protein and show that loss of PTCD1 is embryonic lethal, whereas haploinsufficient, heterozygous mice develop age-induced obesity. The molecular defects and metabolic consequences of mitochondrial protein haploinsufficiency in vivo have not been investigated previously. We show that PTCD1 haploinsufficiency results in increased RNA metabolism, in response to decreased protein synthesis and impaired RNA processing that affect the biogenesis of the respiratory chain, causing mild uncoupling and changes in mitochondrial morphology. We demonstrate that with age, these effects lead to adult-onset obesity that results in liver steatosis and cardiac hypertrophy in response to tissue-specific differential regulation of the mammalian target of rapamycin pathways. Our findings indicate that changes in mitochondrial gene expression have long-term consequences on energy metabolism, providing evidence that haploinsufficiency of PTCD1 can be a major predisposing factor for the development of metabolic syndrome.