•Structured empirical evidence of science, technology and innovation (STI) policies in small, developing economies.•Identification of barriers to design and implement STI policies in small, ...developing economies.•A conceptual framework to analyse STI policies in small and developing economies.•Central American governments have strengthen recently STI institutions and policies, and moved gradually towards a non-linear and systemic approach.•Central American governments face significant barriers to design and implement STI policies, some of them common to small developing countries and some others specific to Central America.
In the last decade, there has been an increasing recognition among Central American policy makers of the central importance of science, technology and innovation (STI) for inclusive and sustainable economic growth, based on higher productivity. This paper aims to study current STI policies in those countries and explore whether this increasing acknowledgement has come along with new and more active policies. Empirical evidence collected through questionnaire-based interviews with high-level government officials in each country shows that Central American governments have built public organisations and institutions to support STI, such as laws, national plans and a wide variety of policy instruments. Yet available science and technology indicators illustrate that the results are still meagre. This paper identifies eight barriers faced by these governments when designing and implementing STI policies.
The geometrical accuracy of georeferenced digital surface models (DTM) obtained from images captured by micro-UAVs and processed by using structure from motion (SfM) photogrammetry depends on several ...factors, including flight design, camera quality, camera calibration, SfM algorithms and georeferencing strategy. This paper focusses on the critical role of the number and location of ground control points (GCP) used during the georeferencing stage. A challenging case study involving an area of 1200+ ha, 100+ GCP and 2500+ photos was used. Three thousand, four hundred and sixty-five different combinations of control points were introduced in the bundle adjustment, whilst the accuracy of the model was evaluated using both control points and independent check points. The analysis demonstrates how much the accuracy improves as the number of GCP points increases, as well as the importance of an even distribution, how much the accuracy is overestimated when it is quantified only using control points rather than independent check points, and how the ground sample distance (GSD) of a project relates to the maximum accuracy that can be achieved.
Under pro-inflammatory conditions, astrocytes become reactive and acquire a migratory phenotype. Our results show that hemichannels formed by connexin 43 (Cx43) play an important role in ...Thy-1-induced astrocyte migration. The neuronal protein Thy-1 binds to αvβ3 integrin in astrocytes, thereby leading to intricate signaling pathways that include calcium (Ca2+) release from intracellular stores, opening of Cx43 hemichannels, release of ATP, activation of P2X7 receptor, and Ca2+ influx. However, because these Thy-1 effects occur exclusively in reactive astrocytes, we wondered whether by elevating calcium levels and promoting hemichannel opening we could prompt non-reactive astrocytes to respond to Thy-1. Cx43 immunoreactivity increased at juxta-membrane sites, where hemichannels (not gap junctions) participate in astrocyte polarization and migration stimulated by Thy-1. Also, intracellular Ca2+ increase, due to ionomycin treatment, induced hemichannel opening, but activated astrocyte migration only partially, and this limitation was overcome by pre-treatment with tumor necrosis factor (TNF) and Thy-1. Finally, αvβ3 integrin formed membrane clusters after TNF stimulation or overexpression of β3 integrin. We suggest that these microclusters are required for cells to respond to Thy-1 stimulation. Therefore, the large increase in intracellular Ca2+ and hemichannel opening induced by ionomycin are required, but not sufficient, to permit Thy-1-induced astrocyte migration. Thus, we suggest that proinflammatory stimuli prompt astrocytes to respond to migratory signals of neuronal cells.
Mobile technologies used for education may offer advantages for children with Communication Disorders, among which we can find language disorders and speech disorders, which are identified in DSM-V. ...In this research, we have introduced two educational activities, “Matching Cards” and “Cards & Sounds”, based on the Montessori Method and which deal with the first stages of reading and writing. We have tested these two activities with children with and without Communication Disorders in order to study how they interact. These groups of children use a Tablet to perform the two activities, which vary in visual and auditory stimuli. The activities employ two touch interactions: tap and drag & drop. Based on Montessori, the activity and the interaction do not produce either positive or negative feedback. The analysis performed with the variables of time, interaction and mistake has shown that children from both groups change their efficiency of use. Differences regarding the interaction of children with and without Communication Disorders have also been observed. Additionally, children with Communication Disorders need additional strategies as explicit indicators in the interaction which may be a guide to be able to carry out specific actions.
Aim The Mediterranean Basin is threatened by climate change, and there is an urgent need for studies to determine the risk of plant range shift and potential extinction. In this study, we simulate ...potential range shifts of 176 plant species to perform a detailed prognosis of critical range decline and extinction in a transformed mediterranean landscape. Particularly, we seek to answer two pivotal questions: (1) what are the general plant-extinction patterns we should expect in mediterranean landscapes during the 21st century? and (2) does dispersal ability prevent extinction under climate change?
Location Andalusia: southern Iberian Peninsula; 87,597 km
2
; 300 by 520 km.
Methods We gathered information on the dispersal traits of 176 plant species (dispersal vector, average and maximum dispersal distances, shape of the dispersal kernel). We used these data to feed a stochastic dynamic species distribution model (a combination of a cellular automaton with an ensemble of species distribution models) to simulate plant range shift under climate change with realistic dispersal under two different warming scenarios. We compared dispersal and non-dispersal simulations to assess the influence that climate change and species-distribution characteristics exert on plant-extinction patterns. Results The dispersal simulation showed a lower percentage of extinct (-1%) and quasi-extinct species (-19%) than did the non-dispersal simulation. Summer temperatures of 37 °C and 33 °C, respectively, accelerated the critical range decline and extinction rates. The average elevation of the plant populations was the variable with the highest influence on extinction probability. Main conclusions Stochastic dynamic species distribution models proved to be useful when there was lack of data on dispersal distances and population dynamics. Dispersal ability showed minor effectiveness in preventing extinction, but greatly reduced the likelihood of critical range decline for a significant percentage of species.
Abstract
This paper presents the development of an efficient, interactive and fully extendable computer code to analyse hydraulic transients – water hammer – using a generic object-oriented modelling ...and simulation (OOMS) tool to simplify and shorten the development process. OOMS tools provide continuous simulation features by means of ordinary differential equation (ODE) and differential algebraic equation (DAE) solvers, and discrete simulation features by means of event handling algorithms. Previous OOMS tool applications to simulate fluid flow in pipe networks primarily used semi-discrete methods with continuous solvers. A novel aspect of this work is the application of the method of characteristics (MOC) using the discrete simulation features of the OOMS tool. When compared to a code developed with an OOMS tool using a semi-discrete method and to commercial software that uses the MOC, the new code shows much higher accuracy and performance than the former and is similar to the latter in accuracy and calculation time. It has a graphical user interface, and its modularity makes it easily extendable with new components and algorithms. An academic version is available on github.
Thermodynamics of Li+–Crown Ether Interactions in Aqueous Solvent González-Pérez, Ramón; Adams, Stephen; Dowling, Alexander W. ...
The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory,
06/2023, Letnik:
127, Številka:
21
Journal Article
Recenzirano
Lithium ion-based batteries are ubiquitous in modern technology due to applications in personal electronics and high-capacity storage for electric vehicles. Concerns about lithium supply and battery ...waste have prompted interest in lithium recycling methods. The crown ether 12-crown-4 has been studied for its abilities to form stable complexes with lithium ions (Li+). In this paper, molecular dynamics simulations are applied to examine the binding properties of a 12-crown-4–Li+ system in aqueous solution. It was found that 12-crown-4 did not form stable complexes with Li+ in aqueous solution due to the binding geometry which was prone to interference by surrounding water molecules. In addition, the binding properties of sodium ions (Na+) to 12-crown-4 are examined for comparison. Subsequently, calculations were performed with the crown ethers 15-crown-5 and 18-crown-6 to study their complexation with Li+ as well as Na+. It was determined that binding was unfavorable for both types of ions for all three crown ethers tested, though 15-crown-5 and 18-crown-6 showed a marginally greater affinity for Li+ than 12-crown-4. Metastable minima present in the potential of mean force for Na+ render binding marginally more likely there. We discuss these results in the context of membrane-based applications of crown ethers for Li+ separations.
Describir la asociación entre las enfermedades crónicas no transmisibles y la edad, con la hospitalización, desenlaces clínicos graves y las defunciones por COVID-19 en los casos confirmados en ...población mexicana, comparando las tres primeras olas epidemiológicas de la pandemia en México.
Se realizó un análisis transversal utilizando el Sistema de Vigilancia Epidemiológica de Enfermedad Respiratoria Viral para COVID-19.
Sistema de Vigilancia Epidemiológica de Enfermedad Respiratoria Viral en México (SISVER).
Población mexicana confirmada para SARS-CoV-2 registrada en el SISVER.
Los desenlaces graves analizados fueron hospitalización, neumonía, necesidad de ventilación mecánica, ingreso a la UCI y defunción. Se evaluó la asociación (odds ratio OR) entre los desenlaces y las variables clínicas, comparando las tres olas epidemiológicas en México.
Una edad mayor de 65 años se asocia a un mayor porcentaje de hospitalización, neumonía, y notablemente, con el total de defunciones, independientemente del efecto de las comorbilidades crónicas. Existe interacción entre la edad en conjunto con la obesidad, la cual se asocia con la hospitalización y neumonía. Estos hallazgos fueron consistentes a lo largo de las tres olas epidemiológicas.
La obesidad, EPOC y la diabetes en interacción con la edad se asocian con peores desenlaces clínicos, primordialmente con defunciones en los pacientes con COVID-19.
To describe the association between chronic noncommunicable diseases and age with hospitalization, death and severe clinical outcomes for COVID-19 in confirmed cases within the mexican population, comparing the first three epidemiological waves of the pandemic in Mexico.
We performed an analysis using Mexico's Government Epidemiological Surveillance System database for COVID-19.
Mexico's Epidemiological Surveillance System for Respiratory Diseases.
Mexican population confirmed with SARS-CoV-2 registered on Mexico's Epidemiological Surveillance System for Respiratory Diseases.
The analysed severe outcomes were hospitalization, pneumonia, use of mechanical ventilation, intensive care unit admission and death. The association (odds ratio) between the outcomes and clinical variables was evaluated, comparing the three epidemiological waves in Mexico.
Age over 65 is associated with a higher ratio of hospitalization and pneumonia, independent of the effect of chronic comorbidities. There is an interaction between age and obesity, which is associated with hospitalization, pneumonia and highly associated with death. These findings were consistent throughout the three epidemiological waves.
Obesity, COPD and diabetes in interaction with age, are associated with worse clinical outcomes and, more importantly, death in patients with COVID-19.
Biological changes that occur during metastatic progression of breast cancer are still incompletely characterized. In this study, we compared intrinsic molecular subtypes and gene expression in 123 ...paired primary and metastatic tissues from breast cancer patients. Intrinsic subtype was identified using a PAM50 classifier and χ
tests determined the differences in variable distribution. The rate of subtype conversion was 0% in basal-like tumors, 23.1% in HER2-enriched (HER2-E) tumors, 30.0% in luminal B tumors, and 55.3% in luminal A tumors. In 40.2% of cases, luminal A tumors converted to luminal B tumors, whereas in 14.3% of cases luminal A and B tumors converted to HER2-E tumors. We identified 47 genes that were expressed differentially in metastatic versus primary disease. Metastatic tumors were enriched for proliferation-related and migration-related genes and diminished for luminal-related genes. Expression of proliferation-related genes were better at predicting overall survival in metastatic disease (OSmet) when analyzed in metastatic tissue rather than primary tissue. In contrast, a basal-like gene expression signature was better at predicting OSmet in primary disease compared with metastatic tissue. We observed correlations between time to tumor relapse and the magnitude of changes of proliferation, luminal B, or HER2-E signatures in metastatic versus primary disease. Although the intrinsic subtype was largely maintained during metastatic progression, luminal/HER2-negative tumors acquired a luminal B or HER2-E profile during metastatic progression, likely reflecting tumor evolution or acquisition of estrogen independence. Overall, our analysis revealed the value of stratifying gene expression by both cancer subtype and tissue type, providing clinicians more refined tools to evaluate prognosis and treatment.
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