Thermal processes on the Tibetan Plateau(TP)influence atmospheric conditions on regional and global scales.Given this,previous work has shown that soil moisture−driven surface flux variations feed back onto the atmosp...Thermal processes on the Tibetan Plateau(TP)influence atmospheric conditions on regional and global scales.Given this,previous work has shown that soil moisture−driven surface flux variations feed back onto the atmosphere.Whilst soil moisture is a source of atmospheric predictability,no study has evaluated soil moisture−atmosphere coupling on the TP in general circulation models(GCMs).In this study,we use several analysis techniques to assess soil moisture−atmosphere coupling in CMIP6 simulations including:instantaneous coupling indices;analysis of flux and atmospheric behaviour during dry spells;and a quantification of the preference for convection over drier soils.Through these metrics we partition feedbacks into their atmospheric and terrestrial components.Consistent with previous global studies,we conclude substantial inter-model differences in the representation of soil moisture−atmosphere coupling,and that most models underestimate such feedbacks.Focusing on dry spell analysis,most models underestimate increased sensible heat during periods of rainfall deficiency.For example,the model-mean bias in anomalous sensible heat flux is 10 W m−2(≈25%)smaller compared to observations.Deficient dry-spell sensible heat fluxes lead to a weaker atmospheric response.We also find that most GCMs fail to capture the negative feedback between soil moisture and deep convection.The poor simulation of feedbacks in CMIP6 experiments suggests that forecast models also struggle to exploit soil moisture−driven predictability.To improve the representation of land−atmosphere feedbacks requires developments in not only atmospheric modelling,but also surface processes,as we find weak relationships between rainfall biases and coupling indexes.展开更多
The inflexible concept of membrane curvature as an independent property of lipid structures is today obsolete.Lipid bilayers behave as many-body entities with emergent properties that depend on their interactions with...The inflexible concept of membrane curvature as an independent property of lipid structures is today obsolete.Lipid bilayers behave as many-body entities with emergent properties that depend on their interactions with the environment.In particular,proteins exert crucial actions on lipid molecules that ultimately condition the collective properties of the membranes.In this review,the potential of enhanced molecular dynamics to address cell-biology problems is discussed.The cases of membrane deformation,membrane fusion,and the fusion pore are analyzed from the perspective of the dimensionality reduction by collective variables.Coupled lipid-protein interactions as fundamental determinants of large membrane remodeling events are also commented.Finally,novel strategies merging cell biology and physics are considered as future lines of research.展开更多
Clouds play a major role in modulating the biometeorological processes. We studied the influence of cloudiness on four biometeorological variables:daily air temperature(Tair), relative humidity(RH),reference evapotran...Clouds play a major role in modulating the biometeorological processes. We studied the influence of cloudiness on four biometeorological variables:daily air temperature(Tair), relative humidity(RH),reference evapotranspiration(ETr),and photosynthetic active radiation(PAR), recorded at four sites of Andean Páramos in southern Ecuador during 2.5 to 5.5 years. First, we quantified both the cloud cover percentage(Cloud%) creating cloud masks over the visible bands of Landsat 7 images and the sky condition(K_(T)) using the records of solar and extraterrestrial radiation. Second, we estimated KTfrom Cloud%. Finally, we quantified T_(air), RH, ET_(r), and PAR under clear, cloudy, and overcast K_(T) and their dependence on KT. The average Cloud% ranged between 65%–76%, and KTcorroborated the prevailing overcast sky(between 55% and 72.5% of the days) over the páramos. The proposed model performed well in the sites of calibration(R^(2)= 0.80;MBE = 0.00;RMSE = 0.05) and validation(R^(2)= 0.74;MBE =-0.07;RMSE = 0.11). The overcast sky diminished T_(air)(≤ 10℃), ET_(r)(≤ 1.6 mm day-1), and PAR(4 MJ m^(-2)day^(-1)) and increased RH(≥ 88%),while the variables showed the opposite behavior during the uncommon clear sky(≤ 5.5% of the days).Thus, mostly the dynamic of RH(R^(2)≥ 0.62), ETr(R^(2)≥ 0.85), and PAR(R2≥ 0.77) depended on K_(T). Hence,the prevailing overcast sky influenced the biometeorology of the páramos.展开更多
Noise pollution is becoming a critical health risk for city life.In 2020,the COVID-19 pandemic forced many cities to implement several mobility restrictions.These restrictions changed human activity patterns and decre...Noise pollution is becoming a critical health risk for city life.In 2020,the COVID-19 pandemic forced many cities to implement several mobility restrictions.These restrictions changed human activity patterns and decreased the noise levels and noise pollution that often affect urban settings.As the number of infections decreased,so did the outdoor activities,influencing the population’s perception of noise.This paper aims to evaluate the changes in noise levels associated with mobility restrictions between 2020 and 2021 in Guayaquil,Ecuador.This study used crowdsourcing with the help of smartphones and mobile applications to collect geo-referenced environmental noise data.The data was used to generate noise maps in different time frames.Finally,noise level maps were created using GIS-based tools to identify the urban areas that experienced the highest noise level variation during the study period.The results show that the most significant noise increase occurred at night.Furthermore,when analyzing noise level changes in different urban areas,the western area of Guayaquil was the one that experienced the most significant noise level variation.Findings inform the perception of noise pollution and could potentially serve as a reference for decision-makers during the proposal of public policies that ensure a better quality of life for its citizens.展开更多
Wood is a lignocellulosic material that,because of its organic nature,is a source of nutrients for bacteria,fungi,and insects.Incisitermes marginipennis(Latreille)is an interesting dry wood-boring termite.Because it i...Wood is a lignocellulosic material that,because of its organic nature,is a source of nutrients for bacteria,fungi,and insects.Incisitermes marginipennis(Latreille)is an interesting dry wood-boring termite.Because it is an extremely destructive pest,difficult to control due to its cryptic lifestyle,and for its role in the biogeochemical cycle of carbon and other elements;it is a fundamental organism.The use of less toxic and eco-friendly substances is important for protecting domestic,cultural,and historical heritage made of wood or lignocellulosic materials.The aim of this study was to evaluate the biological activity of various naphthoquinones extracted from the heartwood of T.grandis on I.marginipennis.First,heartwood flour was used for Soxhlet-type extractions to isolate and characterize the heartwood compounds by thin-layer chromatography.To identify the heartwood compounds,nuclear magnetic resonance and gas chromatography coupled to a mass spectrometer were used.The information obtained was supported using the Interactive Spectroscopy software.The identified heartwood compounds were lapachol,tectoquinone,deoxylapachol,dehydro-α-lapachone,tectol and tecomaquinone-I.Using nymphal termites of I.marginipennis as a biological model,the isolated and identified molecules were under three different tests(repellent,insecticide and protective)and their biological activity was individually evaluated.The results showed that the molecules obtained have a repellent-protective effect against I.marginipennis,although not in all cases,these molecules have high percentages of mortality and decreased the weight loss of the treated material exposed to I.marginipennis.展开更多
Coastal zones, with their significant geodiversity, are vital areas for geotourism. Effective management is crucial to harness the geological interest of these sites as geotourism resources while ensuring their conser...Coastal zones, with their significant geodiversity, are vital areas for geotourism. Effective management is crucial to harness the geological interest of these sites as geotourism resources while ensuring their conservation. ManabíProvince is one of the most representative regions along the Ecuadorian coast due to its beaches and coastal cliffs, offering a wealth of tourist attractions and cultural elements. This study aims to evaluate the geosite potential of six cliffs in ManabíProvince through quantitative and qualitative analyses to propose geotourism promotion strategies. The methodology involves (i) inventory and characterisation of the cliffs, (ii) assessment of the sites by the Spanish Inventory of Places of Geological Interest method (IELIG), and (iii) qualitative evaluation through focus group discussions and Strengths, Weaknesses, Opportunities, and Threats (SWOT) analysis. The results reveal that all six sites boast diverse geological assets, including geomorphological, stratigraphic, sedimentological, and tectonic elements. They are characterised by “high ”scientific, didactic, and tourist interest, while also being sus- ceptible to degradation due to natural and anthropic threats. The SWOT analysis demonstrates that the valuable geological and geomorphological heritage of potential geosites provides an opportunity to foster geotourism and boost the province’s economy, incorporating geoconservation and geoeducation strategies. This study proposes a georoute called “Ruta Acantilados del Sol ”, a 245 km journey encompassing all six sites, incorporating diverse tourist and cultural activities. Our research lays the foundation for fostering geotourism along the Manabícoast and strengthening the connection between nature, heritage, and the welfare of residents within a global resilience plan.展开更多
This present study was conducted to evaluate the metabolic effects of isolated fi ber of carrot supplementation in rats.Physicochemical properties of fi ber were determined.The groups were as follows:animals fed a sta...This present study was conducted to evaluate the metabolic effects of isolated fi ber of carrot supplementation in rats.Physicochemical properties of fi ber were determined.The groups were as follows:animals fed a standard diet,control group;high fi ber supplementation(70 mg);low fi ber supplementation(35 mg);for 12 weeks.Blood samples were collected at the time of sacrifi ce.The weights of heart,liver,kidneys and spleen of the experimental rats with respect to body weight were recorded.Commercial kits were used to determine serum glucose concentration,lipid profi le(cholesterol,HDL-cholesterol,triglycerides),and the two main aminotransferases glutamic-oxalacetic transaminase(GOT)/glutamate-pyruvate transaminase(GPT).A histopathological assay was performed on the heart,liver,and spleen tissues of animals.Supplementation with fi ber favors weight loss in female((242.03±23.73)-(197.81±10.45)g);and male rats((262.50±32.21)-(213.96±12.56)g and induces a decrease in glucose levels in the supplemented animals.With the exception of total high-density lipoprotein cholesterol,the other lipid fractions decrease signifi cantly in rats supplemented.Fiber supplementation did not induce changes in the dissected organs of the supplemented animals.In conclusion supplementation of fiber,improves glucose control,lower plasma lipid concentrations and reduced body weight in normal rats.展开更多
A synthetizing material blended with two distinct proteins (collagen and casein) and mineral mixture, was developed in order to evaluate their properties suitable for possible applications in the biomedical such as in...A synthetizing material blended with two distinct proteins (collagen and casein) and mineral mixture, was developed in order to evaluate their properties suitable for possible applications in the biomedical such as inducing the regeneration of damaged bone, either due to an accident or illness. Samples were evaluated by 1) Mechanical properties tests under the bending, 2) Scanning electronic microscopy and 3) Infrared spectroscopy were carried out. The results showed that the developed material has breaking strength and structure characteristics associated with the protein used in their composition. This fact suggests that the used protein determines the resistance of the material, in such a way according to the required use, being able to choose appropriate strength and duration either short or long time. The material composition for specific use, in order to find the most suitable mixture for bone replacement, or induce bone recovery, according to the required properties similar to those of damaged living tissue.展开更多
The literature highlights that a severe infection by the fungus Colletotrichum truncatum may be capable of inflicting considerable damage to seeds after harvest, potentially affecting their chemical composition and ph...The literature highlights that a severe infection by the fungus Colletotrichum truncatum may be capable of inflicting considerable damage to seeds after harvest, potentially affecting their chemical composition and physiological quality. Taking into account that currently there is no categorization in terms of susceptibility and tolerance on this pathogen, the present work is presented with the main objective of “Evaluate the influence of Pathogenicity of C. truncatum on the physiological quality (germination, vigor, viability) and biochemical components in different varieties of soybean seeds (Glycine max)” most planted in the region. The work was carried out in the Agrotec laboratory, located in the Municipality of San Alberto (Alto Paraná), using a completely randomized experimental design, with AxB factorial arrangement, where A indicates ten most planted soybean varieties in the region and B with or without artificial inoculation of Colletotrichum truncatum, with twenty treatments and four repetitions. The variables evaluated were: germination, vigor, viability and chemical composition. The data were subjected to analysis of variance and the Tukey test at 5% error. The results showed a significant statistical difference, accepting the alternative hypothesis proposed “The pathogenicity of Colletotrichum truncatum influences the physiological quality (germination, vigor, viability) and biochemical components (saturated and unsaturated fatty acids) in different varieties of soybean seeds (Glycine max)”.展开更多
The Advection-Diffusion Reaction (ADR) equation appears in many problems in nature. This constitutes a general model that is useful in various scenarios, from porous media to atmospheric processes. Particularly, it is...The Advection-Diffusion Reaction (ADR) equation appears in many problems in nature. This constitutes a general model that is useful in various scenarios, from porous media to atmospheric processes. Particularly, it is used at the interface between two fluids where different types of instabilities due to surface mobility may appear. Together with the ADR equation, the Darcy-Brinkman model describes the phenomena known as fingering that appear in different contexts. The study of this type of system gains in complexity when the number of chemical species dissolved in both fluids increases. With more solutes, the increasing complexity of this phenomenon generally requires much computational power. To face the need for more computational resources, we build a solver tool based on an Alternating Direction Implicit (ADI) scheme that can be run in Central Processing Unit (CPU) and Graphic Processing Unit (GPU) architectures on any notebook. The implementation is done using the MATLAB platform to compare both versions. It is shown that using the GPU version strongly saves both resources and calculation times.展开更多
In this work, a continuum 2D model is proposed to study the interaction at the interface of reactive transport processes in porous media. The analysis of the segregation produced by poor reactant homogenization at the...In this work, a continuum 2D model is proposed to study the interaction at the interface of reactive transport processes in porous media. The analysis of the segregation produced by poor reactant homogenization at the poral scale is addressed by a parametric heuristic model that considers the relative gradient of the reacting species involved in the process. The micro inhomogeneities are incorporated by means of longitudinal and transversal mechanical dispersion coefficients. A two-dimensional continuous model for the bimolecular reactive transport is considered where modelling parameters are estimated numerically from experimental data. A competitive effect between segregation and dispersion is observed that is analyzed by means of numerical experiments. The two-dimensional model reproduces properly both the total mass of the product as well as its increase with the velocity of flow and the inhomogeneity of the advanced front. The methodology used is simple and fast, and the numerical results presented here indicate its effectiveness.展开更多
In this article, we study the ability of error-correcting quantum codes to increase the fidelity of quantum states throughout a quantum computation. We analyze arbitrary quantum codes that encode all qubits involved i...In this article, we study the ability of error-correcting quantum codes to increase the fidelity of quantum states throughout a quantum computation. We analyze arbitrary quantum codes that encode all qubits involved in the computation, and we study the evolution of n-qubit fidelity from the end of one application of the correcting circuit to the end of the next application. We assume that the correcting circuit does not introduce new errors, that it does not increase the execution time (i.e. its application takes zero seconds) and that quantum errors are isotropic. We show that the quantum code increases the fidelity of the states perturbed by quantum errors but that this improvement is not enough to justify the use of quantum codes. Namely, we prove that, taking into account that the time interval between the application of the two corrections is multiplied (at least) by the number of qubits n (due to the coding), the best option is not to use quantum codes, since the fidelity of the uncoded state over a time interval n times smaller is greater than that of the state resulting from the quantum code correction.展开更多
This study undertook a comprehensive sedimentological and grain-size analysis of two previously uncharacterized volcanoclastic deposits exposed in the northwestern sector of Chihuahua City, Mexico. The primary objecti...This study undertook a comprehensive sedimentological and grain-size analysis of two previously uncharacterized volcanoclastic deposits exposed in the northwestern sector of Chihuahua City, Mexico. The primary objective was to propose a systematic genetic classification for these deposits, employing traditional sedimentological techniques and an advanced computerized granulometric analysis technique based on orthogonal images to discern their grain size distribution. Through these studies, evidence was sought to classify them genetically, presenting arguments to define them either as a lahar or a volcanic debris avalanche. Results were critically compared against existing literature data pertaining to lahars and debris avalanches, yielding moderate success. The analysis identified one of the deposits as a non-eruptive or post-eruptive lahar. This identification was substantiated by the delineation of distinct overbank and transition facies within the deposit, providing compelling evidence for its genetic classification.展开更多
Mg–Xwt.%Ni(X=5 and 20)alloys have been prepared by mechanical alloying using milling times of 15 and 30 h in a planetary ball milling to know the effects of magnesium with the addition of Ni as catalyst,dispersion on...Mg–Xwt.%Ni(X=5 and 20)alloys have been prepared by mechanical alloying using milling times of 15 and 30 h in a planetary ball milling to know the effects of magnesium with the addition of Ni as catalyst,dispersion on the microstructure,area surface and the efficiency of hydrogen storage.SEM-EDS,XRD and ImageJ^(■)software have been used to characterize the microstructure and chemical composition of the alloys.Hydriding experiments were performed as batch-type tests at 200,250 and 300℃ under 2 MPa H2 pressure during 30 min.These experiments resulted in varying amounts of MgH2 in the hydrided powders depending on composition and hydriding conditions.The best results point to an optimum Ni dispersion,which in turn depends on Ni content and milling time.展开更多
K2Ti6O13 whiskers were synthesized by conventional sol-gel method, sono-chemical assisted and microwave assisted sol-gel method in order to obtain catalysts with different particle sizes and to modify their optical, t...K2Ti6O13 whiskers were synthesized by conventional sol-gel method, sono-chemical assisted and microwave assisted sol-gel method in order to obtain catalysts with different particle sizes and to modify their optical, textural and electrochemical properties. These modifications improved their photocatalytic activity for H2 evolution and CO2 photo-reduction. Long K2Ti6O13 whiskers prepared by ultrasound assisted sol-gel method are the most active photocatalysts for the hydrogen evolution reaction using pure water as reactant (U-SG, 10,065 μmol g^-1). In contrast, an opposite behavior was observed using a mixture of ethanol-water, where the highest activity was achieved by the shortest and less crystalline K2Ti6O13 whiskers (C-SG, 3,2871 μmol g^-1). In case of CO2 photo-reduction, long whiskers that were also prepared by the sono-chemical assisted sol-gel method were the most active to transform CO2 to formaldehyde, methane, methanol and hydrogen. The EFB value of this catalyst is located very close to the potential for formaldehyde production and favors the selectivity to this organic product.展开更多
Determining underlying factors that foster deforestation and delineating forest areas by levels of susceptibility are of the main challenges when defining policies for forest management and planning at regional scale....Determining underlying factors that foster deforestation and delineating forest areas by levels of susceptibility are of the main challenges when defining policies for forest management and planning at regional scale. The susceptibility to deforestation of remaining forest ecosystems (shrubland, temperate forest and rainforest) was conducted in the state of San Luis Potosi, located in north central Mexico. Spatial analysis techniques were used to detect the deforested areas in the study area during 1993-2007. Logistic regression was used to relate explanatory variables (such as social, investment, forest production, biophysical and proximity factors) with susceptibility to deforestation to construct predictive models with two focuses: general and by biogeographical zone.In all models, deforestation has positive correlation with distance to rainfed agriculture, and negative correlation with slope, distance to roads and distance to towns. Other variables were significant in some cases, but in others they had dual relationships, which varied in each biogeographical zone. The results show that the remaining rainforest of Huastecaregion is highly susceptible to deforestation. Both approaches show that more than 70% of the current rainforest area has high and very high levels of susceptibility to deforestation. The values represent a serious concern with global warming whether tree carbon is released to atmosphere. However, after some considerations, encouraging forest environmental services appears to be the best alternative to achieve sustainable forest management.展开更多
In finite element modeling of impact,it is necessary to define appropriate values of the normal contact stiffness,Kn,and the Integration Time Step(ITS).Because impacts are usually of very short duration,very small ITS...In finite element modeling of impact,it is necessary to define appropriate values of the normal contact stiffness,Kn,and the Integration Time Step(ITS).Because impacts are usually of very short duration,very small ITSs are required.Moreover,the selection of a suitable value of Kn is a critical issue,as the impact behavior depends dramatically on this parameter.In this work,a number of experimental tests and finite element analyses have been performed in order to obtain an appropriate value of Kn for the interaction between a bristle of a gutter brush for road sweeping and a concrete surface.Furthermore,a suitable ITS is determined.The experiments consist of releasing a steel bristle that is placed vertically at a certain distance from a concrete surface and tracking the impact.Similarly,in the finite element analyses,a beam is modeled in free fall and impacting a surface;contact and target elements are attached to the beam and the surface,respectively.The results of the experiments and the modeling are integrated through the principle of conservation of energy,the principle of linear impulse and momentum,and Newton’s second law.The results demonstrate that,for the case studied,Kn and the impact time tend to be independent of the velocity just before impact and that Kn has a very large variation,as concrete is a composite material with a rough surface.Also,the ratio between the largest height of the bristle after impact and the initial height tends to be constant.展开更多
The removal efficiency of Cu and Zn from swine wastewater was evaluated as effected by three variables: the hydraulic retention time (HRT) (24, 48, 72 and 96 hours), two different plant species (Typha domingensis Pers...The removal efficiency of Cu and Zn from swine wastewater was evaluated as effected by three variables: the hydraulic retention time (HRT) (24, 48, 72 and 96 hours), two different plant species (Typha domingensis Pers. and Eleocharis cellulosa) and two different sizes of filter media (5 and 15 mm) using a horizontal sub-surface flow constructed wetland. From the results, a significant difference was observed in the removal efficiency of Cu and Zn with respect to different hydraulic retention times. The best results were obtained in the HRT of 96 hours for Zn where 96% removal of Zn with Typha domingensis Pers. specie with gravel of 15 mm (experimental unit 6) was achieved. For Cu, at 72 hours of HRT, the efficiency was nearly 100% in five of the six study units (1, 2, 3, 5 and 6). In contrast, in experimental unit 4 with gravel of 15 mm and without plants, only 86% Cu removal was achieved.展开更多
This paper presents the erosion results of the AISI H13 steel impinged by resin-bonded silica sand, using a testing rig that closely simulates the real blowing conditions during industrial core-making. Steel specimens...This paper presents the erosion results of the AISI H13 steel impinged by resin-bonded silica sand, using a testing rig that closely simulates the real blowing conditions during industrial core-making. Steel specimens were heat treated to obtain hardness of 294, 445 and 595 HV200 (29, 45 and 55 HRC). Erosion tests were carried out at impingement angles from 20° to 90° and air drag pressures of 1.38, 2.07 and 2.76 bar (20, 30 and 40 psi). The main results are summarized as follows:(i) The harder material, the lower erosion;(ii) the maximum erosion rate is at 30°;(iii) Little difference in erosion rate at impact angle of 60° and 90° for a constant pressure tested regardless of the hardness level;(iv) As the pressure increases, so does the erosion rate, being more sensitive for low impact angles. Finally, a differential form of the general erosion equation is applied on a practical core-making case to evaluate the erosion rate of the H13 steel at 30° and 90° impingement angles.展开更多
基金supported by the UK-China Research Innovation Partnership Fund through the Met Office Climate Science for Service Partnership (CSSP) China as part of the Newton Fundsupported by the Natural Environment Research Council as part of the NC-International programme (NE/X006247/1) delivering National Capability
文摘Thermal processes on the Tibetan Plateau(TP)influence atmospheric conditions on regional and global scales.Given this,previous work has shown that soil moisture−driven surface flux variations feed back onto the atmosphere.Whilst soil moisture is a source of atmospheric predictability,no study has evaluated soil moisture−atmosphere coupling on the TP in general circulation models(GCMs).In this study,we use several analysis techniques to assess soil moisture−atmosphere coupling in CMIP6 simulations including:instantaneous coupling indices;analysis of flux and atmospheric behaviour during dry spells;and a quantification of the preference for convection over drier soils.Through these metrics we partition feedbacks into their atmospheric and terrestrial components.Consistent with previous global studies,we conclude substantial inter-model differences in the representation of soil moisture−atmosphere coupling,and that most models underestimate such feedbacks.Focusing on dry spell analysis,most models underestimate increased sensible heat during periods of rainfall deficiency.For example,the model-mean bias in anomalous sensible heat flux is 10 W m−2(≈25%)smaller compared to observations.Deficient dry-spell sensible heat fluxes lead to a weaker atmospheric response.We also find that most GCMs fail to capture the negative feedback between soil moisture and deep convection.The poor simulation of feedbacks in CMIP6 experiments suggests that forecast models also struggle to exploit soil moisture−driven predictability.To improve the representation of land−atmosphere feedbacks requires developments in not only atmospheric modelling,but also surface processes,as we find weak relationships between rainfall biases and coupling indexes.
基金Grants from CONICET(PIP-0409CO)ANPCyT(PICT2020-1897)are gratefully acknowledged。
文摘The inflexible concept of membrane curvature as an independent property of lipid structures is today obsolete.Lipid bilayers behave as many-body entities with emergent properties that depend on their interactions with the environment.In particular,proteins exert crucial actions on lipid molecules that ultimately condition the collective properties of the membranes.In this review,the potential of enhanced molecular dynamics to address cell-biology problems is discussed.The cases of membrane deformation,membrane fusion,and the fusion pore are analyzed from the perspective of the dimensionality reduction by collective variables.Coupled lipid-protein interactions as fundamental determinants of large membrane remodeling events are also commented.Finally,novel strategies merging cell biology and physics are considered as future lines of research.
基金National Science Foundation of the United States of America through“A research network for the resilience of headwater systems and water availability for downstream communities across the Americas”funded by the Vice-rectorate for Research of the University of Cuenca。
文摘Clouds play a major role in modulating the biometeorological processes. We studied the influence of cloudiness on four biometeorological variables:daily air temperature(Tair), relative humidity(RH),reference evapotranspiration(ETr),and photosynthetic active radiation(PAR), recorded at four sites of Andean Páramos in southern Ecuador during 2.5 to 5.5 years. First, we quantified both the cloud cover percentage(Cloud%) creating cloud masks over the visible bands of Landsat 7 images and the sky condition(K_(T)) using the records of solar and extraterrestrial radiation. Second, we estimated KTfrom Cloud%. Finally, we quantified T_(air), RH, ET_(r), and PAR under clear, cloudy, and overcast K_(T) and their dependence on KT. The average Cloud% ranged between 65%–76%, and KTcorroborated the prevailing overcast sky(between 55% and 72.5% of the days) over the páramos. The proposed model performed well in the sites of calibration(R^(2)= 0.80;MBE = 0.00;RMSE = 0.05) and validation(R^(2)= 0.74;MBE =-0.07;RMSE = 0.11). The overcast sky diminished T_(air)(≤ 10℃), ET_(r)(≤ 1.6 mm day-1), and PAR(4 MJ m^(-2)day^(-1)) and increased RH(≥ 88%),while the variables showed the opposite behavior during the uncommon clear sky(≤ 5.5% of the days).Thus, mostly the dynamic of RH(R^(2)≥ 0.62), ETr(R^(2)≥ 0.85), and PAR(R2≥ 0.77) depended on K_(T). Hence,the prevailing overcast sky influenced the biometeorology of the páramos.
文摘Noise pollution is becoming a critical health risk for city life.In 2020,the COVID-19 pandemic forced many cities to implement several mobility restrictions.These restrictions changed human activity patterns and decreased the noise levels and noise pollution that often affect urban settings.As the number of infections decreased,so did the outdoor activities,influencing the population’s perception of noise.This paper aims to evaluate the changes in noise levels associated with mobility restrictions between 2020 and 2021 in Guayaquil,Ecuador.This study used crowdsourcing with the help of smartphones and mobile applications to collect geo-referenced environmental noise data.The data was used to generate noise maps in different time frames.Finally,noise level maps were created using GIS-based tools to identify the urban areas that experienced the highest noise level variation during the study period.The results show that the most significant noise increase occurred at night.Furthermore,when analyzing noise level changes in different urban areas,the western area of Guayaquil was the one that experienced the most significant noise level variation.Findings inform the perception of noise pollution and could potentially serve as a reference for decision-makers during the proposal of public policies that ensure a better quality of life for its citizens.
基金supported by the Coordination of Scientific Research,UMSNH(Project 2022).
文摘Wood is a lignocellulosic material that,because of its organic nature,is a source of nutrients for bacteria,fungi,and insects.Incisitermes marginipennis(Latreille)is an interesting dry wood-boring termite.Because it is an extremely destructive pest,difficult to control due to its cryptic lifestyle,and for its role in the biogeochemical cycle of carbon and other elements;it is a fundamental organism.The use of less toxic and eco-friendly substances is important for protecting domestic,cultural,and historical heritage made of wood or lignocellulosic materials.The aim of this study was to evaluate the biological activity of various naphthoquinones extracted from the heartwood of T.grandis on I.marginipennis.First,heartwood flour was used for Soxhlet-type extractions to isolate and characterize the heartwood compounds by thin-layer chromatography.To identify the heartwood compounds,nuclear magnetic resonance and gas chromatography coupled to a mass spectrometer were used.The information obtained was supported using the Interactive Spectroscopy software.The identified heartwood compounds were lapachol,tectoquinone,deoxylapachol,dehydro-α-lapachone,tectol and tecomaquinone-I.Using nymphal termites of I.marginipennis as a biological model,the isolated and identified molecules were under three different tests(repellent,insecticide and protective)and their biological activity was individually evaluated.The results showed that the molecules obtained have a repellent-protective effect against I.marginipennis,although not in all cases,these molecules have high percentages of mortality and decreased the weight loss of the treated material exposed to I.marginipennis.
基金ESPOL Polytechnic University research project:“Register of geological and mining heritage and its incidence in the defence and preservation of geodiversity in Ecuador”with institu-tional code CIPAT-01-2018.
文摘Coastal zones, with their significant geodiversity, are vital areas for geotourism. Effective management is crucial to harness the geological interest of these sites as geotourism resources while ensuring their conservation. ManabíProvince is one of the most representative regions along the Ecuadorian coast due to its beaches and coastal cliffs, offering a wealth of tourist attractions and cultural elements. This study aims to evaluate the geosite potential of six cliffs in ManabíProvince through quantitative and qualitative analyses to propose geotourism promotion strategies. The methodology involves (i) inventory and characterisation of the cliffs, (ii) assessment of the sites by the Spanish Inventory of Places of Geological Interest method (IELIG), and (iii) qualitative evaluation through focus group discussions and Strengths, Weaknesses, Opportunities, and Threats (SWOT) analysis. The results reveal that all six sites boast diverse geological assets, including geomorphological, stratigraphic, sedimentological, and tectonic elements. They are characterised by “high ”scientific, didactic, and tourist interest, while also being sus- ceptible to degradation due to natural and anthropic threats. The SWOT analysis demonstrates that the valuable geological and geomorphological heritage of potential geosites provides an opportunity to foster geotourism and boost the province’s economy, incorporating geoconservation and geoeducation strategies. This study proposes a georoute called “Ruta Acantilados del Sol ”, a 245 km journey encompassing all six sites, incorporating diverse tourist and cultural activities. Our research lays the foundation for fostering geotourism along the Manabícoast and strengthening the connection between nature, heritage, and the welfare of residents within a global resilience plan.
基金the Barcelo Foundation for the financial contribution.
文摘This present study was conducted to evaluate the metabolic effects of isolated fi ber of carrot supplementation in rats.Physicochemical properties of fi ber were determined.The groups were as follows:animals fed a standard diet,control group;high fi ber supplementation(70 mg);low fi ber supplementation(35 mg);for 12 weeks.Blood samples were collected at the time of sacrifi ce.The weights of heart,liver,kidneys and spleen of the experimental rats with respect to body weight were recorded.Commercial kits were used to determine serum glucose concentration,lipid profi le(cholesterol,HDL-cholesterol,triglycerides),and the two main aminotransferases glutamic-oxalacetic transaminase(GOT)/glutamate-pyruvate transaminase(GPT).A histopathological assay was performed on the heart,liver,and spleen tissues of animals.Supplementation with fi ber favors weight loss in female((242.03±23.73)-(197.81±10.45)g);and male rats((262.50±32.21)-(213.96±12.56)g and induces a decrease in glucose levels in the supplemented animals.With the exception of total high-density lipoprotein cholesterol,the other lipid fractions decrease signifi cantly in rats supplemented.Fiber supplementation did not induce changes in the dissected organs of the supplemented animals.In conclusion supplementation of fiber,improves glucose control,lower plasma lipid concentrations and reduced body weight in normal rats.
文摘A synthetizing material blended with two distinct proteins (collagen and casein) and mineral mixture, was developed in order to evaluate their properties suitable for possible applications in the biomedical such as inducing the regeneration of damaged bone, either due to an accident or illness. Samples were evaluated by 1) Mechanical properties tests under the bending, 2) Scanning electronic microscopy and 3) Infrared spectroscopy were carried out. The results showed that the developed material has breaking strength and structure characteristics associated with the protein used in their composition. This fact suggests that the used protein determines the resistance of the material, in such a way according to the required use, being able to choose appropriate strength and duration either short or long time. The material composition for specific use, in order to find the most suitable mixture for bone replacement, or induce bone recovery, according to the required properties similar to those of damaged living tissue.
文摘The literature highlights that a severe infection by the fungus Colletotrichum truncatum may be capable of inflicting considerable damage to seeds after harvest, potentially affecting their chemical composition and physiological quality. Taking into account that currently there is no categorization in terms of susceptibility and tolerance on this pathogen, the present work is presented with the main objective of “Evaluate the influence of Pathogenicity of C. truncatum on the physiological quality (germination, vigor, viability) and biochemical components in different varieties of soybean seeds (Glycine max)” most planted in the region. The work was carried out in the Agrotec laboratory, located in the Municipality of San Alberto (Alto Paraná), using a completely randomized experimental design, with AxB factorial arrangement, where A indicates ten most planted soybean varieties in the region and B with or without artificial inoculation of Colletotrichum truncatum, with twenty treatments and four repetitions. The variables evaluated were: germination, vigor, viability and chemical composition. The data were subjected to analysis of variance and the Tukey test at 5% error. The results showed a significant statistical difference, accepting the alternative hypothesis proposed “The pathogenicity of Colletotrichum truncatum influences the physiological quality (germination, vigor, viability) and biochemical components (saturated and unsaturated fatty acids) in different varieties of soybean seeds (Glycine max)”.
文摘The Advection-Diffusion Reaction (ADR) equation appears in many problems in nature. This constitutes a general model that is useful in various scenarios, from porous media to atmospheric processes. Particularly, it is used at the interface between two fluids where different types of instabilities due to surface mobility may appear. Together with the ADR equation, the Darcy-Brinkman model describes the phenomena known as fingering that appear in different contexts. The study of this type of system gains in complexity when the number of chemical species dissolved in both fluids increases. With more solutes, the increasing complexity of this phenomenon generally requires much computational power. To face the need for more computational resources, we build a solver tool based on an Alternating Direction Implicit (ADI) scheme that can be run in Central Processing Unit (CPU) and Graphic Processing Unit (GPU) architectures on any notebook. The implementation is done using the MATLAB platform to compare both versions. It is shown that using the GPU version strongly saves both resources and calculation times.
文摘In this work, a continuum 2D model is proposed to study the interaction at the interface of reactive transport processes in porous media. The analysis of the segregation produced by poor reactant homogenization at the poral scale is addressed by a parametric heuristic model that considers the relative gradient of the reacting species involved in the process. The micro inhomogeneities are incorporated by means of longitudinal and transversal mechanical dispersion coefficients. A two-dimensional continuous model for the bimolecular reactive transport is considered where modelling parameters are estimated numerically from experimental data. A competitive effect between segregation and dispersion is observed that is analyzed by means of numerical experiments. The two-dimensional model reproduces properly both the total mass of the product as well as its increase with the velocity of flow and the inhomogeneity of the advanced front. The methodology used is simple and fast, and the numerical results presented here indicate its effectiveness.
文摘In this article, we study the ability of error-correcting quantum codes to increase the fidelity of quantum states throughout a quantum computation. We analyze arbitrary quantum codes that encode all qubits involved in the computation, and we study the evolution of n-qubit fidelity from the end of one application of the correcting circuit to the end of the next application. We assume that the correcting circuit does not introduce new errors, that it does not increase the execution time (i.e. its application takes zero seconds) and that quantum errors are isotropic. We show that the quantum code increases the fidelity of the states perturbed by quantum errors but that this improvement is not enough to justify the use of quantum codes. Namely, we prove that, taking into account that the time interval between the application of the two corrections is multiplied (at least) by the number of qubits n (due to the coding), the best option is not to use quantum codes, since the fidelity of the uncoded state over a time interval n times smaller is greater than that of the state resulting from the quantum code correction.
文摘This study undertook a comprehensive sedimentological and grain-size analysis of two previously uncharacterized volcanoclastic deposits exposed in the northwestern sector of Chihuahua City, Mexico. The primary objective was to propose a systematic genetic classification for these deposits, employing traditional sedimentological techniques and an advanced computerized granulometric analysis technique based on orthogonal images to discern their grain size distribution. Through these studies, evidence was sought to classify them genetically, presenting arguments to define them either as a lahar or a volcanic debris avalanche. Results were critically compared against existing literature data pertaining to lahars and debris avalanches, yielding moderate success. The analysis identified one of the deposits as a non-eruptive or post-eruptive lahar. This identification was substantiated by the delineation of distinct overbank and transition facies within the deposit, providing compelling evidence for its genetic classification.
基金Authors acknowledge to PAICYT-UANL 2011-2012the National Council of Science and Technology of Mexico(CONACYT)for the economical support provided by means of project 107063.
文摘Mg–Xwt.%Ni(X=5 and 20)alloys have been prepared by mechanical alloying using milling times of 15 and 30 h in a planetary ball milling to know the effects of magnesium with the addition of Ni as catalyst,dispersion on the microstructure,area surface and the efficiency of hydrogen storage.SEM-EDS,XRD and ImageJ^(■)software have been used to characterize the microstructure and chemical composition of the alloys.Hydriding experiments were performed as batch-type tests at 200,250 and 300℃ under 2 MPa H2 pressure during 30 min.These experiments resulted in varying amounts of MgH2 in the hydrided powders depending on composition and hydriding conditions.The best results point to an optimum Ni dispersion,which in turn depends on Ni content and milling time.
基金CONACYT (CB-2014-237049, PDCPN-2015-487 and Ph. D. scholarship 635249) for the financial support
文摘K2Ti6O13 whiskers were synthesized by conventional sol-gel method, sono-chemical assisted and microwave assisted sol-gel method in order to obtain catalysts with different particle sizes and to modify their optical, textural and electrochemical properties. These modifications improved their photocatalytic activity for H2 evolution and CO2 photo-reduction. Long K2Ti6O13 whiskers prepared by ultrasound assisted sol-gel method are the most active photocatalysts for the hydrogen evolution reaction using pure water as reactant (U-SG, 10,065 μmol g^-1). In contrast, an opposite behavior was observed using a mixture of ethanol-water, where the highest activity was achieved by the shortest and less crystalline K2Ti6O13 whiskers (C-SG, 3,2871 μmol g^-1). In case of CO2 photo-reduction, long whiskers that were also prepared by the sono-chemical assisted sol-gel method were the most active to transform CO2 to formaldehyde, methane, methanol and hydrogen. The EFB value of this catalyst is located very close to the potential for formaldehyde production and favors the selectivity to this organic product.
文摘Determining underlying factors that foster deforestation and delineating forest areas by levels of susceptibility are of the main challenges when defining policies for forest management and planning at regional scale. The susceptibility to deforestation of remaining forest ecosystems (shrubland, temperate forest and rainforest) was conducted in the state of San Luis Potosi, located in north central Mexico. Spatial analysis techniques were used to detect the deforested areas in the study area during 1993-2007. Logistic regression was used to relate explanatory variables (such as social, investment, forest production, biophysical and proximity factors) with susceptibility to deforestation to construct predictive models with two focuses: general and by biogeographical zone.In all models, deforestation has positive correlation with distance to rainfed agriculture, and negative correlation with slope, distance to roads and distance to towns. Other variables were significant in some cases, but in others they had dual relationships, which varied in each biogeographical zone. The results show that the remaining rainforest of Huastecaregion is highly susceptible to deforestation. Both approaches show that more than 70% of the current rainforest area has high and very high levels of susceptibility to deforestation. The values represent a serious concern with global warming whether tree carbon is released to atmosphere. However, after some considerations, encouraging forest environmental services appears to be the best alternative to achieve sustainable forest management.
文摘In finite element modeling of impact,it is necessary to define appropriate values of the normal contact stiffness,Kn,and the Integration Time Step(ITS).Because impacts are usually of very short duration,very small ITSs are required.Moreover,the selection of a suitable value of Kn is a critical issue,as the impact behavior depends dramatically on this parameter.In this work,a number of experimental tests and finite element analyses have been performed in order to obtain an appropriate value of Kn for the interaction between a bristle of a gutter brush for road sweeping and a concrete surface.Furthermore,a suitable ITS is determined.The experiments consist of releasing a steel bristle that is placed vertically at a certain distance from a concrete surface and tracking the impact.Similarly,in the finite element analyses,a beam is modeled in free fall and impacting a surface;contact and target elements are attached to the beam and the surface,respectively.The results of the experiments and the modeling are integrated through the principle of conservation of energy,the principle of linear impulse and momentum,and Newton’s second law.The results demonstrate that,for the case studied,Kn and the impact time tend to be independent of the velocity just before impact and that Kn has a very large variation,as concrete is a composite material with a rough surface.Also,the ratio between the largest height of the bristle after impact and the initial height tends to be constant.
文摘The removal efficiency of Cu and Zn from swine wastewater was evaluated as effected by three variables: the hydraulic retention time (HRT) (24, 48, 72 and 96 hours), two different plant species (Typha domingensis Pers. and Eleocharis cellulosa) and two different sizes of filter media (5 and 15 mm) using a horizontal sub-surface flow constructed wetland. From the results, a significant difference was observed in the removal efficiency of Cu and Zn with respect to different hydraulic retention times. The best results were obtained in the HRT of 96 hours for Zn where 96% removal of Zn with Typha domingensis Pers. specie with gravel of 15 mm (experimental unit 6) was achieved. For Cu, at 72 hours of HRT, the efficiency was nearly 100% in five of the six study units (1, 2, 3, 5 and 6). In contrast, in experimental unit 4 with gravel of 15 mm and without plants, only 86% Cu removal was achieved.
基金financially supported by NEMAK S.A. and Industria Meccanica Bassi Luigi&Co
文摘This paper presents the erosion results of the AISI H13 steel impinged by resin-bonded silica sand, using a testing rig that closely simulates the real blowing conditions during industrial core-making. Steel specimens were heat treated to obtain hardness of 294, 445 and 595 HV200 (29, 45 and 55 HRC). Erosion tests were carried out at impingement angles from 20° to 90° and air drag pressures of 1.38, 2.07 and 2.76 bar (20, 30 and 40 psi). The main results are summarized as follows:(i) The harder material, the lower erosion;(ii) the maximum erosion rate is at 30°;(iii) Little difference in erosion rate at impact angle of 60° and 90° for a constant pressure tested regardless of the hardness level;(iv) As the pressure increases, so does the erosion rate, being more sensitive for low impact angles. Finally, a differential form of the general erosion equation is applied on a practical core-making case to evaluate the erosion rate of the H13 steel at 30° and 90° impingement angles.
