La formación del concepto de función en alumnos de educación media superior

En este artículo se describe la realización de un taller cuyo diseño responde al marco de una investigación en proceso, que explora los saberes que sobre el concepto de función tienen los alumnos de educación media superior (EMS) y pretende analizar los efectos que presenta la puesta en escena de situaciones didácticas sobre la formación del concepto de función. En la primera etapa de la investigación se están explorando dichos saberes en 30 alumnos de EMS y 10 de los primeros semestres de la licenciatura en matemáticas en Acapulco, Guerrero, México. También se han diseñado situaciones didácticas para abordar este concepto, a fin de que se instrumenten en la escuela. Con estos avances se estructuró el taller para interesados en este campo y realizado en Relme 17 con la participación de siete profesores

Spatial Analysis for Conservation Status Assessment within Natura 2000 Network in Forest Area "Prado de Robledela" (Ávila, Spain).

The aim of the Directive 92/43/EEC (EEC, 1992), commonly known as Habitats DireCli\c. "sha11 be to contribute towards ensuring bio-diversity through the cOl1selvation 01' natural habitats and of wild fauna and flora in the European teITitory of lhe Member Stales lo which the Treaty applies" (Article 2). Because of it, it is necessary to ensure the pertinent measures which may help to evaluate the status conservation (Article La) 01' the natural habitats included in Natura 2000 Network. To facilitate this work il is necessary to compil~ and process this information with GIS tools

Un Algoritmo Evolutivo para Resolver el Problema de Coloración Robusta

Let G and \bar{G} be two complementary graphs. Given a penalty function defined over the edges of \bar{G}, it is said that the rigidity of a k-coloring of G is the summation ofthe penalties of the edges of G that join vertices whose endpoint are equally colored. Based on this previous definition, the Robust Coloring Problem is set when searching the valid k-coloring of minimum rigidity. Yáñez and Ramírez proved that this is an NP-hard problem. In this work we present an evolutive algorithm based in the scatter search technique, which obtains optimal solutions for those instances for which an optimal solution is known, and obtains the best known solutions compared to other heuristics, such as: simulated annealing, tabu search and partial enumeration.Sean G y bar{G} un par de gráficas complementarias. Dada una función de peso definida sobre las aristas de \bar{G}, se dice que la rigidez de una k-coloración válida de G es la suma de los pesos de las aristas de \bar{G} que unen vértices del mismo color. Con base en la anterior definición, se plantea el Problema de Coloración Robusta al buscar la k-coloración válida de rigidez mínima. Yáñez y Ramírez probaron que este problema es NP-duro. En este trabajo se presenta un algoritmo evolutivo basado en la técnica de búsqueda dispersa, la cual obtiene soluciones óptimas, en las instancias para las que se conoce la solución óptima, y obtiene las mejores soluciones conocidas comparadas con otras heurísticas, tales como: recocido simulado, búsqueda tabú y enumeración parcial

Proposal of new Natura 2000 network boundaries in Spain based on the value of importance for biodiversity and connectivity analysis for its improvement

The aim of the Natura 2000 Network is to ensure the conservation of habitats and species in their natural areas of distribution. Connectivity is an essential part of this conservation. For this purpose, a value map of importance for biodiversity (V.I.B) was generated proposing 4 levels of protection and overlapped with the Natura 2000 network. New boundaries for the zoning are proposed adding 1.600.000 ha. Two connectivity indices (MSPA and PC) are calculated in the 4 different scenarios. With these indices it is possible to know the number of existing nuclei and connectors in each of the scenarios. New boundaries cover more areas of interest for biodiversity as well as zones of great importance in relation to connectivity. We propose a uniform method that can be extrapolated to any European territor

Evaluating European Conservation Areas and Proposal of New Zones of Conservation under the Habitats Directive. Application to Spanish Territories

The European Union (EU) ensures the conservation of biodiversity through the Natura 2000 Network, which establishes the classification and selection of protected areas at European level. Unfortunately, member countries cannot make the best zoning decisions for biodiversity conservation because there are no clear and uniform parameters to designate Natura 2000 sites. Due to this, it is convenient to evaluate the importance of the criteria for biodiversity conservation through a general assessment, which could establish relevant criteria that can be analysed through geostatistical methods combined in multicriteria analysis. This paper aims to consider biodiversity importance values taking into account land use, so that it is possible to develop a zoning proposal which verifies or corrects the suitability of the designated areas for the Natura 2000 Network in Castilla y León, Andalucía and Madrid (Spain). The choice of these regions allows us to compare areas with a high variability of population density, making possible to compare the potential protected areas with respect to the population living in each area. This assessment has been performed using basic and easily adaptable criteria of biodiversity conservation, so it could be applied in other European territories. In this way, clear and uniform parameters for zoning will be used, being possible to detect the best protected areas. One of the most important purposes of the Natura 2000 Network is to increase connectivity between territories; our work proposes new areas that could be linked to currently protected territories, to favour the achievement of this purpose of the Natura 2000 Network

Comparison of body fat percentage assessments by bioelectrical impedance analysis, anthropometrical prediction equations, and dual-energy X-ray absorptiometry in older women

Background: Individuals with high body fat have a higher risk of mortality. Numerous anthropometric-based predictive equations are available for body composition assessments; furthermore, bioelectrical impedance analysis (BIA) estimates are available. However, in older adults, the validity of body fat estimates requires further investigation. Objective: To assess the agreement between percentage body fat (BF%) estimates by BIA and five predictive equations based on anthropometric characteristics using dual X-ray absorptiometry (DXA) as reference method. A secondary objective was to identify whether excluding short-stature women improves the agreement of BF% estimates in a group of community-dwelling, older Mexican women. Methods: A concordance analysis of BF% was performed. A total of 121 older women participated in the study. Anthropometric information, BIA, and DXA body composition estimates were obtained. Five equations using anthropometric data were evaluated in order to determine body fat percentage (BF%) using DXA as reference method. Paired t-test comparisons and standard error of estimates (SEE) were obtained. The Bland-Altman plot with 95% limits of agreement and the concordance correlation coefficient (CCC) were used to evaluate the BF% prediction equations and BIA estimates. Results: The mean age of the study participants was 73.7 ( 5.8) years old. BIA and the anthropometric based equations examined showed mean significant differences when tested in the entire sample. For the taller women (height > 145 cm), no significant difference in the paired comparison was found between DXA and BIA of BF% estimates. The mean BF% was 40.3 ( 4.8) and 40.7 ( 6.2) for DXA and BIA, respectively. The concordance between methods was good (CCC 0.814), (SEE 2.62). Also, in the taller women subset, the Woolcott equation using waist-to-height ratio presented no significant difference in the paired comparison; however, the error of the estimates was high (SEE 3.37) and the concordance was moderate (CCC 0.693). Conclusion: This study found that BIA yielded good results in the estimation of BF% among women with heights over 145 cm. Also, in this group, theWoolcott predictive equation based on waist circumference and height ratio showed no significant differences compared to DXA in the paired comparison; however, the large error of estimates observed may limit its application. In older women, short stature may impact the validity of the body fat percentage estimates of anthropometric-based predictive equations

Lipoxygenase and Its Relationship with Ethylene During Ripening of Genetically Modified Tomato (Solanum lycopersicum)

Pozadina istraživanja. TomloxB je glavna izoforma lipoksigenaze koja utječe na dozrijevanje i starenje voća, dok je etilen, biljni hormon koji se oslobađa u obliku plina, nužan za regulaciju sazrijevanja klimakteričnog voća poput rajčice. No, odnos između izoforme TomloxB i proizvodnje etilena nije dosad detaljno istražen. Stoga je svrha ovoga rada bila procijeniti učinak dodatka etilena na sazrijevanje transgene rajčice koja sadržava utišani gen TomloxB i odrediti aktivnosti lipoksigenaze i oksidaze 1-aminociklopropan-1-karboksilne kiseline te proizvodnju etilena u plodu rajčice. Također je određena ekspresija gena koji kodiraju oksidazu 1-aminociklopropan-1-karboksilne kiseline i gen TomloxB. Eksperimentalni pristup. Za istraživanje utjecaja lipoksigenaze i oksidaze 1-aminociklopropan-1-karboksilne kiseline, voće je brano u različitim fazama dozrijevanja ploda: pri prvoj pojavi ružičaste boje, kad je cijeli plod ružičast i potpuno crveni plod. Proizvodnja etilena i ekpresija gena određeni su u transgenim rajčicama i onima divljeg tipa ubranim u fazi kad plod tek poprima ružičastu boju. Genetički modificirane rajčice i divlji tip rajčica tretirane su s 100 μL/L etilena. Zatim je spektrofotometrijski mjerena aktivnost lipoksigenaze. Aktivnost oksidaze 1-aminociklopropan-1-karboksilne kiseline i prozvodnja etilena određeni su plinskom kromatografijom. Za određivanje ekspresije gena metodom PCR u stvarnom vremenu upotrijebljeni su oligonukleotidi za različito eksprimirane gene, i to za oksidazu 1-aminociklopropan-1-karboksilne kiseline i TomloxB. Rezultati i zaključci. Dobiveni podaci pokazuju da se utišavanjem gena TomloxB smanjila aktivnost lipoksigenaze i proizvodnja etilena u plodovima rajčice, ali i aktivnost oksidaze 1-aminociklopropan-1-karboksilne kiseline. Posljedično tome, dodatak etilena povećao je aktivnost lipoksigenaze u svim uzorcima, a aktivnost oksidaze 1-aminociklopropan-1-karboksilne kiseline samo u transgenim linijama, i to u fazi u kojoj plod poprima ružičastu boju. Dodatak etilena inducirao je pozitivnu regulaciju gena TomloxB, jer se povećanjem količine etilena povećala i aktivnost lipoksigenaze. Rezultati pokazuju da lipoksigenaza može kontrolirati oksidazu 1-aminociklopropan-1-karboksilne kiseline i proizvodnju etilena u fazi zrelosti u kojoj plod poprima ružičastu boju. Novina i znanstveni doprinos. Rezultati ovog rada pridonose boljem razumijevanju metaboličke funkcije izoforme TomloxB u sazrijevanju ploda te načina na koji je povezana s procesima starenja, čime se može produljiti rok trajanja voća. Razumijevanje odnosa između lipoksigenaze i etilena korisno je za bolje rukovanje plodovima rajčica nakon berbe.Research background. TomloxB is the main isoform of lipoxygenase associated with ripening and senescence of fruits. On the other hand, ethylene, a gaseous hormone, is essential for the regulation of ripening in climacteric fruits like tomatoes. However, the relationship between TomloxB and ethylene production has not been thoroughly studied. Therefore, we aim to assess the effect of exogenous ethylene in transgenic tomatoes that contain a silenced TomloxB gene, and subsequently evaluate lipoxygenase activity, 1-aminocyclopropane-1-carboxylic acid oxidase and ethylene production; as well as to quantify the expression of the genes encoding 1-aminocyclopropane-1-carboxylic acid oxidase and TomloxB. Experimental approach. To investigate the effect of lipoxygenase and 1-aminocyclopropane-1-carboxylic acid oxidase activity, fruits harvested at the stages of break, turning and pink were used. Tomatoes at break stage collected from transgenic and wild type plants were used to determine ethylene production and gene expression. Genetically modified and wild type tomato fruits were exposed to 100 μL/L exogenous ethylene. Lipoxygenase activity was measured spectrophotometrically. Activity of 1-aminocyclopropane-1-carboxylic acid oxidase and ethylene production were determined by gas chromatography. Oligonucleotides for differentially expressed genes: 1-aminocyclopropane-1-carboxylic acid oxidase and TomloxB were used to determine gene expression by real-time PCR. Results and conclusions. The data showed that silencing of TomloxB caused a reduction in lipoxygenase activity and ethylene production in tomato fruits, and also reduced 1-aminocyclopropane-1-carboxylic acid oxidase activity. Hence, the addition of exogenous ethylene increased lipoxygenase activity in all treatments and 1-aminocyclopropane-1-carboxylic acid oxidase activity only in transgenic lines at break stage, consequently there was a positive regulation between TomloxB and ethylene, as increasing the amount of ethylene increased the activity of lipoxygenase. The results suggest that lipoxygenase may be a regulator of 1-aminocyclopropane-1-carboxylic acid oxidase and production of ethylene at break stage. Novelty and scientific contribution. These results lead to a better understanding of the metabolic contribution of TomloxB in fruit ripening and how it is linked to the senescence-related process, which can lead to a longer shelf life of fruits. Understanding this relationship between lipoxygenase and ethylene can be useful for better post-harvest handling of tomatoes

Dental care and risk of developing severe COVID-19

During the COVID-19 pandemic, dental care was recommended only in urgent and severe pain cases. Reduced dental appointments may affect the financial situation of dentists, especially those who are not financially secure. Due to economic necessity, dentists are required to provide care despite the risk of being infected with SARS-COV-2. Objective: To describe the frequency of dental care and the risk of complications due to COVID-19 among dentists in Ixtlahuaca, State of Mexico, Mexico. Material and methods: Cross-sectional study, non-probabilistic sampling carried out from August to September 2020. A survey was carried out through social networks to identify thefrequency of dental care. Results: The sample consisted of 121 dentists with an average age of 32.3 years. Women comprised most of the sample (74.4%). Dentists had a medium risk of suffering complications due to COVID-19 (92.5%). Private practice dentists performed more non-urgent treatments during the red and orange epidemiological risk periods, showing statistically significant differences (p≤0.05). Unhealthy weight was present in 30% of the sample. Conclusions: Dentists have a medium risk of becoming seriously ill from COVID-19. The risk is associated with unhealthy weight. Dentists performed non-urgent treatments despite government recommendations. Privatepractitioners performed a greater number of non-urgent treatments. Dentists provide care despite epidemiological risk related to COVID-19 due to economic necessity

Basophil-lineage commitment in acute promyelocytic leukemia predicts for severe bleeding after starting therapy

Severe hemorrhagic events occur in a significant fraction of acute promyelocytic leukemia patients, either at presentation and/or early after starting therapy, leading to treatment failure and early deaths. However, identification of independent predictors for high-risk of severe bleeding at diagnosis, remains a challenge. Here, we investigated the immunophenotype of bone marrow leukemic cells from 109 newly diagnosed acute promyelocytic leukemia patients, particularly focusing on the identification of basophil-related features, and their potential association with severe bleeding episodes and patient overall survival. From all phenotypes investigated on leukemic cells, expression of the CD203c and/or CD22 basophil-associated markers showed the strongest association with the occurrence and severity of bleeding (p ≤ 0.007); moreover, aberrant expression of CD7, coexpression of CD34+/CD7+ and lack of CD71 was also more frequently found among patients with (mild and severe) bleeding at baseline and/or after starting treatment (p ≤ 0.009). Multivariate analysis showed that CD203c expression (hazard ratio: 26.4; p = 0.003) and older age (hazard ratio: 5.4; p = 0.03) were the best independent predictors for cumulative incidence of severe bleeding after starting therapy. In addition, CD203c expression on leukemic cells (hazard ratio: 4.4; p = 0.01), low fibrinogen levels (hazard ratio: 8.8; p = 0.001), older age (hazard ratio: 9.0; p = 0.002), and high leukocyte count (hazard ratio: 5.6; p = 0.02) were the most informative independent predictors for overall survival. In summary, our results show that the presence of basophil-associated phenotypic characteristics on leukemic cells from acute promyelocytic leukemia patients at diagnosis is a powerful independent predictor for severe bleeding and overall survival, which might contribute in the future to (early) risk-adapted therapy decisions.This work was supported by the Fundación Científica de la Asociación Española Contra el Cáncer (AECC, Madrid, Spain) and the Fundación Rafael del Pino (Madrid, Spain) and both CIBERONC (CB16/12/00400, CB16/12/00233, CB16/12/00480) and grant PI16/00787 from Instituto de Salud Carlos III (Ministerio de Economía y Competitividad, Madrid, Spain)

Behavioral and Cytological Differences between Two Parkinson’s Disease Experimental Models

The knowledge about the biochemical and behavioral changes in humans with PD has allowed proposing animal models for its study; however, the results obtained so far have been heterogeneous. Recently, we established a novel PD model in rodents by manganese chloride (MnCl2) and manganese acetate (Mn (OAc)3) mixture inhalation. After inhaling, the rodents presented bilateral loss of SNc dopaminergic neurons. Later, we conclude that the alterations are of dopamine origin since L-DOPA reverted the alterations. After six months, SNc significantly reduced the number of cells, and striatal dopamine content decreased by 71%. The animals had postural instability, action tremor, and akinesia; these symptoms improved with L-DOPA, providing evidence that Mn mixture inhalation induces comparable alterations that those in PD patients. Thus, this study aimed to compare the alterations in two different PD experimental models: 6-OHDA unilateral lesion and Mn mixture inhalation through open field test, rotarod performance and the number of SNc dopaminergic neurons. The results show that the Mn-exposed animals have motor alterations and bilateral and progressive SNc neurons degeneration; in contrast, in the 6-OHDA model, the neuronal loss is unilateral and acute, demonstrating that the Mn exposure model better recreates the characteristics observed in PD patients