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"Martinez, Alejandra"
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Impacts of digital technologies on education and factors influencing schools' digital capacity and transformation: A literature review
by
Giannoutsou, Nikoleta
,
Ioannou, Andri
,
Cachia, Romina
in
Change Strategies
,
Computer Appl. in Social and Behavioral Sciences
,
Computer Science
2023
Digital technologies have brought changes to the nature and scope of education and led education systems worldwide to adopt strategies and policies for ICT integration. The latter brought about issues regarding the quality of teaching and learning with ICTs, especially concerning the understanding, adaptation, and design of the education systems in accordance with current technological trends. These issues were emphasized during the recent COVID-19 pandemic that accelerated the use of digital technologies in education, generating questions regarding digitalization in schools. Specifically, many schools demonstrated a lack of experience and low digital capacity, which resulted in widening gaps, inequalities, and learning losses. Such results have engendered the need for schools to learn and build upon the experience to enhance their digital capacity and preparedness, increase their digitalization levels, and achieve a successful digital transformation. Given that the integration of digital technologies is a complex and continuous process that impacts different actors within the school ecosystem, there is a need to show how these impacts are interconnected and identify the factors that can encourage an effective and efficient change in the school environments. For this purpose, we conducted a non-systematic literature review. The results of the literature review were organized thematically based on the evidence presented about the impact of digital technology on education and the factors that affect the schools’ digital capacity and digital transformation. The findings suggest that ICT integration in schools impacts more than just students’ performance; it affects several other school-related aspects and stakeholders, too. Furthermore, various factors affect the impact of digital technologies on education. These factors are interconnected and play a vital role in the digital transformation process. The study results shed light on how ICTs can positively contribute to the digital transformation of schools and which factors should be considered for schools to achieve effective and efficient change.
Journal Article
Role of Interleukin 6 in Innate Immunity to Mycobacterium tuberculosis Infection
2013
Background. Mycobacterium tuberculosis can grow in the hostile intracellular environment of macrophages by actively evading macrophage-associated antibacterial activities. The stress response factor SigH contributes to this process by modulating β-chemokine and interleukin 6 (Il6) expression. Hence, Il6 is of critical importance for acquired immunity against M. tuberculosis infection. Here, we attempted to better characterize the role of Il6 in the immune response to M. tuberculosis infection. Methods. A small interfering RNA—based approach was used to silence expression of the Il6 transcript in host macrophages infected with a wild-type strain of M. tuberculosis or an attenuated mutant strain of M. tuberculosis (Mtb:Δ-sigH). The outcome was measured by the analysis of bacterial burden and transcriptome-wide analysis of host gene expression. Transcriptome results were confirmed via quantitative polymerase chain reaction and enzyme-linked immunosorbent assay. Results. Wild type and Mtb:Δ-sigH infection of host macrophages in which Il6 had been silenced resulted in increased expression of interferon-inducible genes, especially those involved in type I interferon signaling. The expression of Ly-6 genes was significantly higher in cells infected with Mtb:Δ-sigH, compared with those infected with the wild-type strain (P < .05). Conclusions. M. tuberculosis regulates host Il6 production to inhibit type I interferon signaling and, consequently, disease progression. Mtb:Δ-sigH is associated with delayed activation of macrophages, compared with the wild-type strain, and with delayed inflammatory stimuli as consequence. These findings have important implications for improving understanding of the mechanisms behind M. tuberculosis virulence and pathogenesis and provide an initial road map to further investigate the mechanisms that may account for the deleterious effects of type I interferons in M. tuberculosis infection.
Journal Article
Silvopastoral systems and remnant forests enhance carbon storage in livestock-dominated landscapes in Mexico
by
Ramírez-Díaz, Roselia
,
La O Arias, Manuel Alejandro
,
Jiménez-Trujillo, José Antonio
in
631/158/2458
,
631/158/670
,
704/106/694/682
2022
A large area of the terrestrial land surface is used for livestock grazing. Trees on grazing lands provide and can enhance multiple ecosystem services such as provisioning, cultural and regulating, that include carbon sequestration. In this study, we assessed the above- and belowground carbon stocks across six different land-uses in livestock-dominated landscapes of Mexico. We measured tree biomass and soil organic carbon (SOC) stocks in fodder banks, live fences, pasturelands with dispersed trees, secondary forests, and primary forests from three different geographical regions and compared them with conventional open pasturelands respectively. We also calculated tree diversity indices for each land-use and their similarity with native primary forests. The aboveground woody biomass stocks differed significantly between land-uses and followed the gradient from less diverse conventional open pasturelands to silvopastoral systems and ecologically complex primary forests. The SOC stocks showed a differential response to the land-use gradient dependent on the study region. Multivariate analyses showed that woody biomass, fine root biomass, and SOC concentrations were positively related, while land-use history and soil bulk density showed an inverse relationship to these variables. Silvopastoral systems and forest remnants stored 27–163% more carbon compared to open pasturelands. Our results demonstrate the importance of promoting appropriate silvopastoral systems and conserving forest remnants within livestock-dominated landscapes as a land-based carbon mitigation strategy. Furthermore, our findings also have important implications to help better manage livestock-dominated landscapes and minimize pressures on natural protected areas and biodiversity in the hotspots of deforestation for grassland expansion.
Journal Article
PCR-Based Techniques for Leprosy Diagnosis: From the Laboratory to the Clinic
by
Moraes, Milton Ozório
,
Talhari, Sinésio
,
Talhari, Carolina
in
Biology and Life Sciences
,
Care and treatment
,
Causes of
2014
In leprosy, classic diagnostic tools based on bacillary counts and histopathology have been facing hurdles, especially in distinguishing latent infection from active disease and diagnosing paucibacillary clinical forms. Serological tests and IFN-gamma releasing assays (IGRA) that employ humoral and cellular immune parameters, respectively, are also being used, but recent results indicate that quantitative PCR (qPCR) is a key technique due to its higher sensitivity and specificity. In fact, advances concerning the structure and function of the Mycobacterium leprae genome led to the development of specific PCR-based gene amplification assays for leprosy diagnosis and monitoring of household contacts. Also, based on the validation of point-of-care technologies for M. tuberculosis DNA detection, it is clear that the same advantages of rapid DNA detection could be observed in respect to leprosy. So far, PCR has proven useful in the determination of transmission routes, M. leprae viability, and drug resistance in leprosy. However, PCR has been ascertained to be especially valuable in diagnosing difficult cases like pure neural leprosy (PNL), paucibacillary (PB), and patients with atypical clinical presentation and histopathological features compatible with leprosy. Also, the detection of M. leprae DNA in different samples of the household contacts of leprosy patients is very promising. Although a positive PCR result is not sufficient to establish a causal relationship with disease outcome, quantitation provided by qPCR is clearly capable of indicating increased risk of developing the disease and could alert clinicians to follow these contacts more closely or even define rules for chemoprophylaxis.
Journal Article
Interacting pest control and pollination services in coffee systems
by
Chain-Guadarrama, Adina
,
Martínez-Salinas, Alejandra
,
Cerda, Rolando
in
Biodiversity
,
Biological Sciences
,
Birds
2022
Biodiversity-mediated ecosystem services (ES) support human well-being, but their values are typically estimated individually. Although ES are part of complex socioecological systems, we know surprisingly little about how multiple ES interact ecologically and economically. Interactions could be positive (synergy), negative (trade-offs), or absent (additive effects), with strong implications for management and valuation. Here, we evaluate the interactions of two ES, pollination and pest control, via a factorial field experiment in 30 Costa Rican coffee farms. We found synergistic interactions between these two critical ES to crop production. The combined positive effects of birds and bees on fruit set, fruit weight, and fruit weight uniformity were greater than their individual effects. This represents experimental evidence at realistic farm scales of positive interactions among ES in agricultural systems. These synergies suggest that assessments of individual ES may underestimate the benefits biodiversity provides to agriculture and human well-being. Using our experimental results, we demonstrate that bird pest control and bee pollination services translate directly into monetary benefits to coffee farmers. Excluding both birds and bees resulted in an average yield reduction of 24.7% (equivalent to losing US$1,066.00/ha). These findings highlight that habitat enhancements to support native biodiversity can have multiple benefits for coffee, a valuable crop that supports rural livelihoods worldwide. Accounting for potential interactions among ES is essential to quantifying their combined ecological and economic value.
Journal Article
Plant–soil feedbacks depend on drought stress, functional group, and evolutionary relatedness in a semiarid grassland
by
García-Meza, Diego
,
Martorell, Carlos
,
Martínez-Blancas, Alejandra
in
Biota
,
Community composition
,
community structure
2021
Plant–soil feedback (PSF) occurs when plants change the biota and physicochemical properties of the soil, and these changes affect future survival or growth of plants. PSF depends on several factors such as plant functional attributes (e.g., life cycle or photosynthetic metabolism) and the environment. PSF often turn positive under dry conditions because soil biota confers drought tolerance. Conspecifics and close relatives share pathogens and consume similar resources, exerting negative PSF on each other. These ideas have mostly been tested under controlled conditions, while field studies remain scarce. To reevaluate these findings in nature, we analyzed plant–soil feedbacks over a drought-stress gradient in a phosphorus-limited semiarid grassland. We planted seedlings of 17 species in plots where community composition had been monitored for six years. To determine PSF intensity, we measured how seedling longevity was affected by previous occupancy of conspecifics and heterospecifics. The previous occupancy–survival relationship (OSR) was used as a proxy for PSF. Evidence for OSRs was found in one-third of the species pairs, with inconclusive evidence for the rest suggesting weak feedbacks. This is in line with the expectation that PSFs in the field are weaker than under controlled conditions. As expected, positive PSFs were more frequent as drought stress increased. The strongest OSRs were caused in dry plots by C₄ perennial grasses, which had very positive OSRs on several C₃ annual forbs, but negative effects on each other. Well-documented differences between these two functional groups may explain this result: C₃ plants are more sensitive to drought, and thus may be favored by tolerance-conferring microbiota; in contrast, water-efficient C₄ perennial grasses compete for phosphorus strongly, perhaps driving strong negative PSFs between them. Finally, close relatives had more negative OSRs on each other than on distant relatives as expected, although only in dry plots. This pattern was mostly due to the negative effects of closely related C₄ grasses under dry conditions, and their positive effects on distantly related dicots. Our results highlight the importance of plant traits and of the environmental context in determining the direction and strength of PSFs under field conditions.
Journal Article
From Iron to Copper: The Effect of Transition Metal Catalysts on the Hydrogen Storage Properties of Nanoconfined LiBH4 in a Graphene-Rich N-Doped Matrix
by
Gasnier, Aurelien
,
Gennari, Fabiana C.
,
Martínez, Alejandra A.
in
Carbon
,
coordination metal catalyst
,
Graphene
2022
Incipient wetness impregnation was employed to decorate two N-doped graphene-rich matrixes with iron, nickel, cobalt, and copper nanoparticles. The N-doped matrix was wetted with methanol solutions of the corresponding nitrates. After agitation and solvent evaporation, reduction at 800 °C over the carbon matrix promoted the formation of nanoparticles. The mass of the metal fraction was limited to 5 wt. % to determine if limited quantities of metallic nanoparticles catalyze the hydrogen capture/release of nanoconfined LiBH4. Isotherms of nitrogen adsorption afforded the textural characterization of the matrixes. Electronic microscopy displayed particles of definite size, evenly distributed on the matrixes, as confirmed by X-ray diffraction. The same techniques assessed the impact of LiBH4 50 vol. % impregnation on nanoparticle distribution and size. The hydrogen storage properties of these materials were evaluated by differential scanning calorimetry and two cycles of volumetric studies. X-ray diffraction allowed us to follow the evolution of the material after two cycles of hydrogen capture-release. We discuss if limited quantities of coordination metals can improve the hydrogen storage properties of nanoconfined LiBH4, and which critical parameters might restrain the synergies between nanoconfinement and the presence of metal catalysts.
Journal Article
Polyphenolic Compounds and Digestive Enzymes: In Vitro Non-Covalent Interactions
by
Rosa, Laura A. de la
,
Vargas-Requena, Claudia L.
,
Bustos-Jaimes, Ismael
in
Enzymes
,
Humans
,
Hydrogen Bonding
2017
The digestive enzymes–polyphenolic compounds (PCs) interactions behind the inhibition of these enzymes have not been completely studied. The existing studies have mainly analyzed polyphenolic extracts and reported inhibition percentages of catalytic activities determined by UV-Vis spectroscopy techniques. Recently, pure PCs and new methods such as isothermal titration calorimetry and circular dichroism have been applied to describe these interactions. The present review focuses on PCs structural characteristics behind the inhibition of digestive enzymes, and progress of the used methods. Some characteristics such as molecular weight, number and position of substitution, and glycosylation of flavonoids seem to be related to the inhibitory effect of PCs; also, this effect seems to be different for carbohydrate-hydrolyzing enzymes and proteases. The digestive enzyme–PCs molecular interactions have shown that non-covalent binding, mostly by van der Waals forces, hydrogen binding, hydrophobic binding, and other electrostatic forces regulate them. These interactions were mainly associated to non-competitive type inhibitions of the enzymatic activities. The present review emphasizes on the digestive enzymes such as α-glycosidase (AG), α-amylase (PA), lipase (PL), pepsin (PE), trypsin (TP), and chymotrypsin (CT). Existing studies conducted in vitro allow one to elucidate the characteristics of the structure–function relationships, where differences between the structures of PCs might be the reason for different in vivo effects.
Journal Article
“Border closure only increased precariousness”: a qualitative analysis of the effects of restrictive measures during the COVID-19 pandemic on Venezuelan’s health and human rights in South America
by
Olivari, Carla
,
Cabieses, Báltica
,
Rocha-Jimenez, Teresita
in
Biostatistics
,
Border security
,
Borders
2023
Background
In 2010, a political and social crisis pushed thousands of Venezuelans out of their country; today, seven million Venezuelans live abroad. In addition, during the COVID-19 pandemic, border closure increased and affected specific vulnerable migration flows, such as Venezuelans trying to migrate to Chile through the Northern borders. In this context, there is little evidence of migrants’ health status and needs, their access to health services, and other basic needs (e.g., housing) from a human rights perspective. Therefore, we qualitatively explored the effects of border closure due to the COVID-19 pandemic on Venezuelan migrants’ health and human rights, focusing on access to healthcare in the Northern Chilean border that adjoins Peru and Bolivia.
Methods
Following a case-study qualitative design, we conducted an ethnography that included participatory observation of relevant sites (e.g., hospitals, main squares, migrant shelters) in Antofagasta, Iquique, and Arica and 30 in-depth interviews with actors in the health sector (
n
= 7), experts from the non-governmental sector (
n
= 16), and governmental actors (
n
= 7) in three large cities close to the Northern border.
Results
We found four main dimensions: (i) border and migration processes, (ii) specific groups and intersectionality, (iii) barriers to healthcare services, and (iv) regional and local responses to the crisis during the COVID-19 pandemic. Programs characterized by the presence of healthcare providers in the field were essential to attend to migrants’ health needs at borders.
Conclusions
Coordination between actors is crucial to implement regional protocols that respond to current migration phenomena and migrants’ health needs. Health policies using a human rights approach are urgently required to respond to migrants’ healthcare needs at borders in South America.
Journal Article
The role of drought conditions on the recent increase in wildfire occurrence in the high Andean regions of Peru
by
Zubieta, Ricardo
,
Ilbay, Mercy
,
Ccanchi, Yerson
in
Agriculture
,
Andes region
,
Controlled burning
2023
Wildfire occurrence has increased sharply in the last two decades in the Peruvian Andes. There is, however, little research on wildfires and their impacts. This study explores the conditions conducive to wildfire during 2020. MODIS images were collected to estimate the development of vegetation. In addition, ground-based monthly and satellite-based daily precipitation data were collected. Daily precipitation regularity was evaluated using a concentration index (CI), while monthly precipitation was used to estimate the Standard Precipitation Index (SPI). We used also the Global Vegetation Moisture Index (GVMI), which is a useful indicator of vegetation dynamics based on vegetation moisture. Our results do not indicate a direct link between rainfall regularity (lowest CI values) and development of vegetation. Although the SPI drought analysis using seasonal rainfall indicated nearly normal conditions during 2019–2020, analysis of dry-day frequency (DDF) suggests that the dry period played an important role between September and November 2020, producing conditions similar to the droughts of 2005, 2010 and 2016. GVMI also showed below-average values from April to November. We corroborate the usefulness of DDF for monitoring the potential increase in wildfire conditions. A controlled burn policy could offer a more useful way to reduce the impacts of wildfire.
Journal Article