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In this paper, a nonlinear fractional-order chikungunya disease model that incorporates asymptomatic infectious individuals is proposed and analyzed. The main interest of this work is to investigate the role of memory effects on the dynamics of chikungunya. Qualitative analysis of the model's equilibria showed that there exists a threshold quantity which governs persistence and extinction of the disease. Model parameters were estimated based on the 2015 weekly reported cases in Colombia. The Adams-Bashforth-Moulton method was used to numerically solve the proposed model. We investigated the role of asymptomatic infectious patients on short- and long-term dynamics of the diseases. We also determined threshold levels for the efficacy of preventative strategies that results in effective management of the disease. We believe that our model can provide invaluable insights for public health authorities to predict the effect of chikungunya transmission and analyze its underlying factors and to guide new control efforts. [ABSTRACT FROM AUTHOR]

Isostichopus sp. is a variety of Isostichopus badionotus, proposed as a new species, which has been intensely fished in the Colombian Caribbean, arousing interest for its aquaculture. This study evaluated the effect of two culture densities (1–3 larvae ml−1), two temperatures (23°C and 26°C) and two microalgae diets (Isochrysis galbana, Chaetoceros calcitrans, Nannochloropsis oculata 1:1:1 and I. galbana, C. calcitrans 1:1) on the survival, development and growth of its larvae. Larval culture lasted 22 days until metamorphosis to doliolaria larvae, and 7 days later, the first juveniles were observed with a size of 621.8 ± 12.7 µm (±SE). The highest growth rates, survival and percentage of doliolaria larvae were obtained with 1 larva ml−1 (29.2 µm/day and 31.5% doliolaria larvae) and 26°C (28.4 µm/day and 10% doliolaria larvae). However, in the two diets examined, the larvae showed low growth rates (between 1.3 and 8.5 µm/day), stagnation in development and high mortality. Our results indicate that it is feasible to culture larvae from Isostichopus sp. to juveniles, recommending the use of 1 larva ml−1 and 26°C. However, to meet the nutritional needs of the larvae the inclusion of microalgae Pavlova sp. and Tetraselmis chuii in the diet is recommended. This paper reports for the first time the successful production of sea cucumber juveniles of this species in Colombia. [ABSTRACT FROM AUTHOR]

The global COVID-19 outbreak has demanded drastic actions and policies from the governments and local authorities to stem the spread of the virus. Most of the measures involve behavioural changes from citizens to reduce their social contact to a minimum. Thus, these actions influence individual activity patterns and transport systems in different ways. This paper studies the short-term impacts on the transport system caused by the different policies adopted by the Colombian government and local authorities to contain the COVID-19 spread. Using official and secondary data concerning the seven most populated cities in Colombia, we analyse the impacts on three components of the transport system: air transport, freight transport, and urban transport. Results show that national policies and local decisions have decreased the demand for motorised trips across the cities, diminishing congestion levels, reducing transit ridership, and creating a reduction in transport externalities. The country banned air transport for passengers and only allowed air cargo for medical and necessary supplies, which will have negative consequences for the economics of the airline industry. During the first three months of the COVID-19, freight was the most resilient transport component. However, freight trips diminished around 38%, affecting mainly the supply chain of nonessential products. During the pandemic, governments need to provide subsidies to maintain the system supply to avoid crowdedness and promote active transport by allocating less-used street space to cyclists and pedestrians. In the short term, transportation service providers will face a financial crisis, deepened by the pandemic, which will require government assistance for their recovery. [ABSTRACT FROM AUTHOR]

Introduction. Parkinson's disease (PD) is one of the most prevalent age-related neurodegenerative disorders. The progression of PD produces an important disease burden in patients due to functional impairment, which also has repercussions on caregivers. In addition, it has become a challenge for health systems, especially in developing countries, which have limited resources. Multidisciplinary teams with a community approach have proved effective in high-income countries; however, there is no reported literature in low- and middle-income countries about this kind of initiative. Objective. This paper aims to document the experience of patients, caregivers, and experts in a community approach as an innovative model in a middle-income country. Methods. A quantitative descriptive research was conducted. The selection criteria were having a PD diagnosis, attending with a caregiver to Saturdays in Motion (SIM), or being a clinical expert invited to SIM. PD patients and their caregivers answered three surveys on their points of view with respect to SIM: SIM and their quality of life (QoL) and PDQ-39 and Zarit, whereas clinical experts completed two questions related to the SIM program. Descriptive statistics were used to summarize the results of the surveys and clinical tests. Results. Forty-eight, twenty-four, and twenty-one subjects answered surveys one, two, and three, respectively. In total, four clinical experts were interviewed. 87.9% of the patients consider that SIM activities improved their QoL. The most affected areas in PDQ-39 were those related to the social area. Around 66.6% of the caregivers reported a mild burden on Zarit and think that SIM enhances the PD patient's QoL. Clinical experts highlighted the sense of community and empathy. Conclusion. Our preliminary experience shows a multidisciplinary model with a community approach which redefines the traditional relationship between patients, caregivers, and clinical experts. This aim of this initiative is that education and empowerment patients and caregivers reach a better perception of QoL. [ABSTRACT FROM AUTHOR]

This article presents a Generation Expansion Model of the power system taking into account the operational constraints and the uncertainty of long-term electricity demand projections. The model is based on a discretization of the load duration curve and explicitly considers that power plant ramping capabilities must meet demand variations. A model predictive control method is used to improve the long-term planning decisions while considering the uncertainty of demand projections. The model presented in this paper allows integrating technical constraints and uncertainty in the simulations, improving the accuracy of the results, while maintaining feasible computational time. Results are tested over three scenarios based on load data of an energy retailer in Colombia. [ABSTRACT FROM AUTHOR]

The primary angiitis of the central nervous system (PACNS) is an entity with a very low incidence and prevalence. It is not clear why the inflammatory process of this entity is limited to the cerebral vasculature without systemic manifestations. Its clinical manifestations are very heterogeneous and make clinical diagnosis difficult. In most cases, a brain biopsy is required. Only the clinical suspicion and the ability to recognize the possible clinical and imagenological patterns of presentation make an accurate diagnosis possible. The vast majority of the treatment recommendations are given by series of case reports. The following paper described the clinical, imagenological, and histopathological characteristics of three Colombian patients with PACNS.Thestrategic therapeutic used in shown. [ABSTRACT FROM AUTHOR]

The aim of this paper is to actualize the taxonomy of Dorymyrmex, by addressing problems at both the genus and the species levels. We also explore the taxonomy and distribution of Dorymyrmex in Colombia. We list, diagnose, and key nine species in the country, including three new species: Dorymyrmex amazonicus n. sp. Cuezzo & Guerrero, Dorymyrmex xerophylus n. sp. Cuezzo & Guerrero, and Dorymyrmex tuberosus n. sp. Cuezzo & Guerrero. We provide a detailed description of these new species based on the worker caste and, where possible, other castes. All localities where Dorymyrmex was collected or cited in the literature were mapped to provide a graphical view of its range. [ABSTRACT FROM AUTHOR]