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Processes involving soil CO_(2)dynamic in a sector of Chaco-Pampean plain,Argentina:An isotope geochemical approach
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作者 Sanci Romina Panarello Héctor 《Acta Geochimica》 EI CAS CSCD 2024年第5期947-958,共12页
The magnitude and spatial variability of CO_(2)surface emissions and processes involving CO_(2)released to the atmosphere from the soils are relevant issues in the context of climate change.This work evaluated CO_(2)f... The magnitude and spatial variability of CO_(2)surface emissions and processes involving CO_(2)released to the atmosphere from the soils are relevant issues in the context of climate change.This work evaluated CO_(2)fluxes and^(13)C/^(12)C ratio of vegetation,organic matter,and soil gases from no disturbed soils of Chaco Pampean Plain(Argentina)with different soil properties and environmental conditions(PL and PA units).Soil organic decomposition from individual layers was accompanied byδ^(13)C of total organic carbon(δ^(13)C-TOC)values more enriched to depth.δ^(13)C-TOC values in the upper soil profile~ca.0–15 cm were like the plant community of this area(~−33 to−29‰)whileδ^(13)CTOC varied stronger bellow horizon A,till~−24‰.Bothδ^(13)C-TOC and soilδ^(13)C-CO_(2)were similar(~−24 to 26‰)at deeper horizons(~50–60 cm).Toward the superficial layers,δ^(13)C-TOC andδ^(13)C-CO_(2)showed more differences(till~4‰),due influence of the diffusion process.Horizon A layer(~0–20 cm)from both PL and PA units contained the most enrichedδ^(13)C-CO_(2)values(~−15–17‰)because atmospheric CO_(2)permeated the soil air.A simple two-component mixing model between sources(atmosphericδ^(13)C-CO_(2)and soil CO_(2))confirmed that process.Isotopically,CO_(2)fluxes reflected the biodegradation of C3 plants(source),diffusive transport,and CO_(2)exchange(atmosphere/soil).Soil moisture content appeared as a determining factor in the diffusion process and the magnitude of CO_(2)surface emissions(12–60 g·m^(−2)·d^(−1)).That condition was confirmed by CO_(2)diffusion coefficients estimated by air-filled porosity parameters and soil radon gradient model. 展开更多
关键词 Soil CO_(2) Carbon isotopes Isotope fractionation Radon gases
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Tri-axial accelerometry allows to determine parental food provisioning behaviour in a marine bird
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作者 Monserrat Del Caño Flavio Quintana +1 位作者 Giacomo Dell’Omo Agustina Gómez-Laich 《Avian Research》 SCIE CSCD 2024年第3期345-351,共7页
The study of parental food provisioning is essential for understanding the breeding ecology of birds.We conducted the first study using accelerometry to detect food provisioning in birds,using Support Vector Machine(S... The study of parental food provisioning is essential for understanding the breeding ecology of birds.We conducted the first study using accelerometry to detect food provisioning in birds,using Support Vector Machine(SVM)models to identify when adults feed chicks of three different age classes.Accelerometers were attached to the head of adult female Imperial Shags(Leucocarbo atriceps),and various attributes derived from the acceleration signals were used to train SVM models for each chick age class.Model performance improved with chick age class,with SVM models achieving high overall accuracy(>88%)and highest sensitivity in older chick categories(>91%).However,precision values,especially for younger chicks,remained relatively low(between 26%and 45%).The application of a time filter based on the minimum duration of the observed food provisioning behaviours for each chick age category,improved model performance by reducing false provisioning behaviours,particularly in the model for older chicks,which showed the highest precision(72.4%).This study highlights the effectiveness of accelerometry and machine learning in studying parental food provisioning in birds,providing a rapid and accurate data collection method to complement traditional techniques.The described methodology can be applied to any bird species that exhibits distinctive movements while feeding its offspring and has suitable characteristics for attaching an accelerometer to the body part that best captures this movement.Finally,it is hoped that the results of this study will contribute to future research on key questions in parental investment theory and reproductive strategies in birds. 展开更多
关键词 ACCELEROMETRY Food provisioning Imperial shag Leucocarbo atriceps SEABIRD Support vector machine
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Endophytic Occupation in Nodules of Rhynchosia Plants from Semiarid Regions of Argentina
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作者 Cinthia T.Lucero María de los Á.Ruíz +3 位作者 Fabiola Pagliero Carolina Castaño Mariela L.Ambrosino Graciela S.Lorda 《Phyton-International Journal of Experimental Botany》 SCIE 2024年第6期1081-1099,共19页
Beneficial microbes can improve soil health by promoting soil structure,nutrient cycling,and disease suppression.In addition,a wide array of rhizospheric microbes are responsible for producing metabolically active comp... Beneficial microbes can improve soil health by promoting soil structure,nutrient cycling,and disease suppression.In addition,a wide array of rhizospheric microbes are responsible for producing metabolically active compounds including various types of plant growth regulators.So,microbial biodiversity studies could contribute to the improvement of agricultural practices in deprived areas,such as the Pampean semiarid region.The vast majority of studies conducted on endophytic microorganisms have focused on intensive crop legume species.In contrast,little attention has been paid to microorganisms of native legumes,whose ecology is not directly affected by human action.In this study,endophytic microorganisms isolated from root nodules of a selected native legume of the genus Rhynchosia were characterized.Viable isolates were studied with a focus on their plant growth-pro-moting rhizobacteria(PGPR)properties.Considering the edaphic characteristics of the Pampean semiarid region,the isolates obtained were evaluated for their ability to grow under three salt stress conditions(50,100,and 200 mM NaCl)and four different pH values(6,7,8,and 9).Based on their PGPR activities,the selected strains were phylogenetically grouped using BOX-PCR.The results showed great variability among the isolates in terms of the characteristics studied.Native legumes manifested a wide endophytic variability and remarkable perfor-mance in PGPR activities.We conclude that they could be used as potential bioinoculants for legume cultivation,an excellent alternative to the use of chemical fertilizers that currently pollute the environment. 展开更多
关键词 Native strains ENDOPHYTES PGPR native legumes stress
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Shared Memory Semi-Implicit Solver for Hydrodynamical Instability Processes
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作者 Augusto Kielbowicz Diego Fernández +2 位作者 Adriana Saal Claudio El Hasi Carlos Vigh 《Open Journal of Fluid Dynamics》 CAS 2023年第1期32-46,共15页
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
关键词 FINGERING FLUIDS Simulations Numerical Solver Hele-Shaw Cell
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Bird species present in urban parks are more colorful than urban avoiders:A test in the Argentinian Pampas
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作者 Lucas M.Leveau 《Avian Research》 SCIE CSCD 2024年第1期22-26,共5页
Bird plumage color has been assessed as a possible trait driving the presence of bird species in urban areas.Although some species can see the ultraviolet(UV) spectrum,the mentioned studies did not take into account U... Bird plumage color has been assessed as a possible trait driving the presence of bird species in urban areas.Although some species can see the ultraviolet(UV) spectrum,the mentioned studies did not take into account UV reflectance when characterizing bird plumage.This study aimed to use a recent database of the colorfulness in passerines that incorporated the UV spectrum to compare bird colorfulness and other traits between urban parks and rural areas in Central-East Argentina.Birds in urban parks were surveyed in 51 parks in 6 cities during breeding and non-breeding seasons.A list of Passeriformes species from parks was created,and a list of urban avoider species was created from the bibliography.Species traits were body mass,clutch size,migratory status,nesting site,diet and habitat breadth,and plumage colorfulness.A total of 85 species were detected in the regional pool,of which 30 species were detected in urban parks.Bird species present in urban parks were more colorful than bird species only present in rural areas.In addition,bird presence in urban parks was positively related to their regional frequency and diet breadth.Moreover,urban presence was related to nesting on trees and buildings,whereas species not present in urban parks nested on the ground.The results obtained showed that bird color is significantly associated with presence of bird species in urban parks. 展开更多
关键词 AVIAN Filter PHENOTYPE Selection ULTRAVIOLET
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Assessing the Environmental Impact of Extensive Beef Production in Grazing Lands of Argentina
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作者 Ernesto Viglizzo Florencia Ricard 《Phyton-International Journal of Experimental Botany》 SCIE 2024年第8期1943-1962,共20页
Because of environmental constraints,beef cattle was for more than a century the only viable farming option in the extensive semiarid and subhumid lands of Argentina and the main source of nutrients for humans as well... Because of environmental constraints,beef cattle was for more than a century the only viable farming option in the extensive semiarid and subhumid lands of Argentina and the main source of nutrients for humans as well.However,a growing concern and criticism have risen today about its possible negative impact on the climate and the environment.These worries tend to affect current public opinions,national policies,and international trade.Based on 40 beef cattle farms scattered across different semiarid and subhumid regions of Argentina,here we evaluated the impact of extensive cattle production on carbon,water,and nutrient pollution.Life-Cycle Assessment(LCA)and Land-Based Assessment(LBA)were the two approaches we used here to compare the environmental impact of beef production.While the environmental footprint(EF)resulting from LCA expresses the impact per unit of food,the environmental balance(EB),derived from LBA,aims at quantifying the impact per unit of land.As such,the EB considers both negative and positive impacts on the farm as an integrated system.Following standardized procedures,we evaluated EF and EB up to the farm gate,leaving aside delocalized post-farm impacts such as those of processing,packaging,and transportation that occur beyond the farm gate.In agreement with previous evidence,our results show that the EF tends to decrease as per-head production increases.Correlation coefficients and statistical significance were the following for carbon(R=−0.574;p<0.01),water(R=−0.561;p<0.01),and N(R=−0.704;p<0.01)and Phosphorus(P)pollution(R=−0.802;p<0.01)footprints.On the contrary,the EB seems to be highly sensitive,and as per-hectare beef production increases.Correlations were the following for carbon emissions(CE:R=0.955;p<0.01),water consumption(WC:R=0.822;p<0.01),nitrogen excretion(NE:R=0.948;p<0.01)and phosphorus excretion(PE:R=0.945;p<0.01).What our results suggest is that the notion of EF is useful to evaluate the environmental impact in intensive beef production systems,and the EB is suitable to assess the impact of the extensive ones.In practice,both approaches provide different perspectives on the environmental-impact problem and they should be complementary used.We concluded that the methodological rigidity of EF does not allow proper discrimination among farms in the extensive systems.On the contrary,the EB approach tended to be highly sensitive to detecting differences between individual farms and farmers,thus allowing the identification of successful options for extensive beef production in terms of public image,policy-making,and commercial opportunities. 展开更多
关键词 Beef production extensive cattle raising grazing conditions environmental impact assessment
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Validation of a SPME-GC Method for Azoxystrobin and Pyraclostrobin in Blueberries, and Their Degradation Kinetics 被引量:11
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作者 Martín S. Munitz Silvia L. Resnik +1 位作者 María I. T. Montti Silvia Visciglio 《Agricultural Sciences》 2014年第11期964-974,共11页
Analytical method for the residues of strobilurins azoxystrobin and pyraclostrobin in blueberries was developed. Fungicide residues were determined by solid-phase microextraction (SPME) cou-pled to gas chromatography ... Analytical method for the residues of strobilurins azoxystrobin and pyraclostrobin in blueberries was developed. Fungicide residues were determined by solid-phase microextraction (SPME) cou-pled to gas chromatography with micro-electron capture detector. The effect of pH values and fiber coatings were studied. The SPME fiber coating selected was 100 μm PDMS. The method is selective with adequate precision and high accuracy and sensitivity. Recoveries ranged within the 100% - 106% range for azoxystrobin, and 96% - 106% range for pyraclostrobin;and detection and quantification limits were 2.0 and 6.0 μg/kg for azoxystrobin, and 26.0 and 86.0 μg/kg for py-raclostrobin, respectively. Statistical parameters indicated the occurrence of matrix effect;con-sequently calibration was performed on spiked samples. Degradation of azoxystrobin and pyra-clostrobin was studied in blueberry fields located in Concordia, Argentina, with fruits from Emerald and Jewel varieties. The degradation of these fungicides in both blueberry varieties studied followed a first order rate kinetics, and the half-life for azoxystrobin was 11.6 and 17.8 days for Emerald and Jewel cultivars;and for pyraclostrobin was 5.5 and 8.0 days, respectively. 展开更多
关键词 BLUEBERRIES AZOXYSTROBIN PYRACLOSTROBIN DEGRADATION KINETICS SPME/GC
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CD4+ T cells and natural killer cells: Biomarkers for hepatic fibrosis in human immunodeficiency virus/hepatitis C virus-coinfected patients 被引量:2
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作者 Natalia Laufer Diego Ojeda +6 位作者 María Laura Polo Ana Martinez Héctor Pérez Gabriela Turk Pedro Cahn Norberto Walter Zwirner Jorge Quarleri 《World Journal of Hepatology》 CAS 2017年第25期1073-1080,共8页
AIM To characterize peripheral blood natural killer(NK) cells phenotypes by flow cytometry as potential biomarker of liver fibrosis in human immunodeficiency virus(HIV)/hepatitis C virus(HCV) coinfected patients.METHO... AIM To characterize peripheral blood natural killer(NK) cells phenotypes by flow cytometry as potential biomarker of liver fibrosis in human immunodeficiency virus(HIV)/hepatitis C virus(HCV) coinfected patients.METHODS Peripheral mononuclear cells from 24 HIV/HCV(HBVnegative) coinfected and 5 HIV/HCV/HBV seronegative individuals were evaluated. HIV/HCV coinfected patients were divided in to groups: G1, patients with METAVIR F0-F2 and G2, patients with METAVIR F3-F4. NK surface cell staining was performed with: AntiCD3(APC/Cy7), anti-CD56(PE/Cy5), anti-CD57(APC), anti-CD25(PE), anti-CD69(FITC), anti-NKp30(PE), antiNKp46(PE/Cy7), anti-NKG2D(APC), anti-DNAM(FITC); anti-CD62L(PE/Cy7), anti-CCR7(PE), anti-TRAIL(PE), anti-Fas L(PE), anti CD94(FITC). Flow cytometry data acquisition was performed on BD FACSCanto, analyzed using Flow Jo software. Frequency of fluorescence was analyzed for all single markers. Clinical records were reviewed, and epidemiological and clinical data were obtained.RESULTS Samples from 11 patients were included in G1 and from 13 in G2. All patients were on ARV, with undetectable HIV viral load. Liver fibrosis was evaluated by transient elastography in 90% of the patients and with biopsy in 10% of the patients. Mean HCV viral load was(6.18 ± 0.7 log10). Even though, no major significant differences were observed between G1 and G2 regarding NK surface markers, it was found that patients with higher liver fibrosis presented statistically lower percentage of NK cells than individual with low to mild fibrosis and healthy controls(G2: 5.4% ± 2.3%, G1: 12.6% ± 8.2%, P = 0.002 and healthy controls 12.2% ± 2.7%, P = 0.008). It was also found that individuals with higher liver fibrosis presented lower CD4 LT count than those from G1(G2: 521 ± 312 cells/μL, G1: 770 ± 205 cells/μL; P = 0.035).CONCLUSION Higher levels of liver fibrosis were associated with lower percentage of NK cells and LTCD4+ count; and they may serve as noninvasive biomarkers of liver damage. 展开更多
关键词 CD4^+ T cell Human immunodeficiency virus/hepatitis C virus-coinfection FIBROSIS BIOMARKER Natural killer cells
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Does variable stand structure associated with multi-cohort forests support diversity of ground beetle (Coleoptera, Carabidae) communities in the central Nearctic boreal forest? 被引量:1
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作者 Erica P. Barkley Jay R. Malcolm +1 位作者 Sandy M. Smith M. Isabel Bellocq 《Journal of Forestry Research》 SCIE CAS CSCD 2016年第5期1191-1202,共12页
Multi-cohort management (MCM) that retains a range of stand structures (age and size class) has been proposed to emulate natural disturbance and improve management in the Nearctic boreal forest. Although MCM fores... Multi-cohort management (MCM) that retains a range of stand structures (age and size class) has been proposed to emulate natural disturbance and improve management in the Nearctic boreal forest. Although MCM forests contain both single- and multi-aged stands of mixed tree sizes, little is known about how variable stand structure affects associated fauna and biodiversity. Here, we examine the relationship between ground beetle (Coleoptera, Carabidae) communities and stand characteristics across a range of forest structure (=cohort classes). Given that MCM classes are defined by the distribution of their tree-stem diameters, we ask whether parameters associated with these distributions (Weibull) could explain observed variation in carabid communities, and if so, how this compares to traditional habitat variables such as stand age, foliage complexity or volume of downed woody debris. We sampled carabids using weekly pitfall collections and compared these with structural habitat variables across a range of cohort classes (stand structure and age since disturbance) in 18 sites of upland mixed boreal forests from central Canada. Results showed that richness and diversity of carabid communities were similar among cohort classes. Weibull parameters from the diameter distribution of all stems were the strongest predictors of variation in carabid communities among sites, but vertical foliage complexity, understory thickness, and percentage of deciduous composition were also significant. The abundance of several carabid forest specialists was strongly correlated with tree canopy height, the presence of large trees, and high vertical foliage complexity. Our results demonstrate that variable forest structure, as expected under MCM, may be useful in retaining the natural range of ground beetle species across the central Nearctic boreal forest. 展开更多
关键词 Biodiversity conservation Boreal forest CARABIDAE Forest structure Ground beetles Multi-cohortmanagement Tree diameter distribution
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Biological Corridors as a Connectivity Tool in the Region of the Great American Chaco:Identification of Biodiversity Hotspots in the Ecoregions of the Paraguayan Chaco 被引量:1
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作者 María Fátima Mereles Gloria Céspedes +7 位作者 JoséLuís Cartes Rosalía Goerzen JuanaDe Egea-Elsam Laura Rodríguez Alberto Yanosky Laura Villalba Andrea Weiler Pier Cacciali 《Research in Ecology》 2020年第1期27-36,共10页
This work presents the main biodiversity hotspots existing in the Paraguayan Chaco and is an update of the results obtained in the first Ecoregional Assessment of the Great American Chaco.These are the results of a se... This work presents the main biodiversity hotspots existing in the Paraguayan Chaco and is an update of the results obtained in the first Ecoregional Assessment of the Great American Chaco.These are the results of a series of workshops that included scientific and technical discussions carried out by local experts in zoology,botany,forestry,soil science,and hydrogeology applying a biodiversity vision of 25-30 years for the territory,after overlapping the maps of the first assessment with that of the advance of the changes of land use in the territory.Criteria for detecting biodiversity hotspots were discussed,including:permanent and temporary watercourses,other bodies of water such as fresh and salty lagoons,reserve areas of different categories,as well as important bird areas(IBAs),RAMSAR areas and others,which must be connected in the future,combining the production areas with the conservation of biodiversity. 展开更多
关键词 Conservation FAUNA FLORA Endemic species Sustainable use
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Geomechanical model for a seismically active geothermal field:Insights from the Tinguiririca volcanic-hydrothermal system
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作者 L.Giambiagi P.Alvarez +5 位作者 S.Spagnotto E.Godoy A.Lossada J.Mescua M.Barrionuevo J.Suriano 《Geoscience Frontiers》 SCIE CAS CSCD 2019年第6期2117-2133,共17页
In this work,we develop a multidisciplinary approach to investigate a geothermal system located at the volcanic arc of a subduction-related orogen and highlight the interplay between active tectonism.stress field and ... In this work,we develop a multidisciplinary approach to investigate a geothermal system located at the volcanic arc of a subduction-related orogen and highlight the interplay between active tectonism.stress field and fluid migration.By using results of field investigations from the Tinguiririca geothermal field in the High Andes of Chile(35°S),empirical analysis,and numerical models of static stress variations,we proposed a geomechanical model for evaluating the distribution of hydrothermal manifestations in a seismically-active region.The present geomechanical model follows four major steps:(1)development of the 3 D structural model of fault pattern;(2)estimation of the in-situ stress field;(3)calculation of the resolved-shear-to-normal-stress ratio(slip tendency)on each fault with varying geomechanical parameters(coefficient of friction,pore pressure and cohesion)as inputs;and(4)estimation of Coulomb static stress changes as a consequence of failure in a nearby fault.Through combination of all these analyses,we characterize in detail both the active deformation in the geothermal field and its relationship with hot fluid migration. 展开更多
关键词 SOUTHERN central ANDES PALEOSTRESS analysis Fluid migration COULOMB staric stress change
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Tree community composition,structure and diversity along an elevational gradient in an Andean forest of Northern Ecuador
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作者 JIMÉNEZ-PAZ Rosa WORTHY Samantha J +4 位作者 VALENCIA Renato PÉREZÁlvaro J REYNOLDS Alex BARONE John A BURGESS Kevin S 《Journal of Mountain Science》 SCIE CSCD 2021年第9期2315-2327,共13页
The Andean forests of northern Ecuador are known for their high levels of plant diversity relative to the area they occupy.Typically,these forests grow on steep slopes that lead to dramatic habitat gradients across sh... The Andean forests of northern Ecuador are known for their high levels of plant diversity relative to the area they occupy.Typically,these forests grow on steep slopes that lead to dramatic habitat gradients across short distances.These extreme habitat gradients make the Andean forest ecosystem an excellent natural laboratory for understanding the effect of elevation on forest community diversity,structure and composition.We established 31 plots(50 m×5 m)which are divided between two elevational transects in the cloud forest of the Siempre Verde Reserve in the western foothills of the Andes Mountains of northern Ecuador.All trees and tree ferns with a diameter at breast height(dbh)≥5 cm were measured and identified.We examined changes in community composition,structure,and diversity along and between the elevational transects and three elevational zones:low(2437–2700 m),middle(2756–3052 m),and high(3163–3334 m).We found four main trends associated with the elevational gradients at this site:(1)community composition differed between the two transects and among the three elevational zones according to N-MDS,ANOSIM,and percentage of shared species,with some species having limited distributions,(2)metrics of community structure showed opposite relationships with elevation,depending on the transect,with the only significant relationship(negative)found between basal area and elevation in the open trail transect,(3)alpha diversity,in general,peaked at mid-elevations,and(4)beta diversity consistently increased with distance between plots along elevation.The complexity of changes in community composition,structure,and alpha diversity along elevation may be related to the heterogeneity of the environment on a local scale,such as topography,soil composition,and even human impact,or to dispersal limitation and should be investigated further.These changes in community composition and the relatively high beta diversity found at this site exemplify the biological complexity of montane forest,reinforcing arguments from other studies on the importance of their conservation. 展开更多
关键词 Elevational gradient Cloud forest ANDES STRUCTURE Composition DIVERSITY
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Cenozoic basin evolution of the Central Patagonian Andes:Evidence from geochronology, stratigraphy, and geochemistry
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作者 A.Encinas A.Folguera +6 位作者 R.Riffo P.Molina L.Fernández Paz V.D.Litvak D.A.Colwyn V.A.Valencia M.Carrasco 《Geoscience Frontiers》 SCIE CAS CSCD 2019年第3期1139-1165,共27页
The Central Patagonian Andes is a particular segment of the Andean Cordillera that has been subjected to the subduction of two spreading ridges during Eocene and Neogene times. In order to understand the Cenozoic geol... The Central Patagonian Andes is a particular segment of the Andean Cordillera that has been subjected to the subduction of two spreading ridges during Eocene and Neogene times. In order to understand the Cenozoic geologic evolution of the Central Patagonian Andes, we carried out geochronologic(U-Pb and^(40)Ar/^(39)Ar), provenance, stratigraphic, sedimentologic, and geochemical studies on the sedimentary and volcanic Cenozoic deposits that crop out in the Meseta Guadal and Chile Chico areas(~47°S). Our data indicate the presence of a nearly complete Cenozoic record, which refutes previous interpretations of a hiatus during the middle Eocene-late Oligocene in the Central Patagonian Andes. Our study suggests that the fluvial strata of the Ligorio Marquez Formation and the flood basalts of the Basaltos Inferiores de la Meseta Chile Chico Formation were deposited in an extensional setting related to the subduction of the Aluk-Farallon spreading ridge during the late Paleocene-Eocene. Geochemical data on volcanic rocks interbedded with fluvial strata of the San Jose Formation suggest that this unit was deposited in an extensional setting during the middle Eocene to late Oligocene. Progressive crustal thinning allowed the transgression of marine waters of Atlantic origin and deposition of the upper Oligocene-lower Miocene Guadal Formation. The fluvial synorogenic strata of the Santa Cruz Formation were deposited as a consequence of an important phase of compressive deformation and Andean uplift during the early-middle Miocene. Finally, alkali flood basalts of the late middle to late Miocene Basaltos Superiores de la Meseta Chile Chico Formation were extruded in the area in response to the suduction of the Chile Ridge under an extensional regime. Our studies indicate that the tectonic evolution of the Central Patagonian Andes is similar to that of the North Patagonian Andes and appears to differ from that of the Southern Patagonian Andes, which is thought to have been the subject of continuous compressive deformation since the late Early Cretaceous. 展开更多
关键词 CENTRAL Patagonian ANDES U-Pb GEOCHRONOLOGY Ar-Ar GEOCHRONOLOGY GEOCHEMISTRY STRATIGRAPHY SEDIMENTOLOGY
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Impact of chitosan-based nanocarriers on cytoskeleton dynamics:Current status and challenges
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作者 M.CAROLINA DI SANTO AGUSTINA ALAIMO +1 位作者 ANA PAULA DOMÍNGUEZ RUBIO OSCAR E.PÉREZ 《BIOCELL》 SCIE 2022年第4期885-891,共7页
Chitosan-based nanocarriers(CS-NCs)show a promising role in improving drugs and bioactive compounds delivery for therapy.However,the effects exerted by CS-NCs at the cellular level,including their recognition and upta... Chitosan-based nanocarriers(CS-NCs)show a promising role in improving drugs and bioactive compounds delivery for therapy.However,the effects exerted by CS-NCs at the cellular level,including their recognition and uptake,have not been fully investigated yet.Many factors,including size,shape,concentration,and surface chemistry of CS-NCs,play an important role in determining the types of intracellular signals triggered.The mechanism of uptake and the involvement of the cytoskeleton during the CS-NCs endocytosis variates among the different cell types as well as further effects observed inside cells.In the present work,we discuss the effects induced by CS-NCs per se on the cytoskeleton,a key component in cell architecture and physiology.The focus of this report is made on tumoral and normal biological models in which CS-NCs could differentially affect the cell cytoskeleton.The recent years reports regarding the impact of CS-NCs on cytoskeleton dynamics and the current techniques for its evaluation are summarized and discussed.Understanding mechanisms underlying cytoskeletal impact after cell exposure to CS-NCs is critical for the design of safest value-added formulations in the biomedical field.Furthermore,this revision points out some interesting aspects of cytoskeletal changes and cell death encompassing anti-tumoral effects. 展开更多
关键词 Cytoskeletal dynamics Cellular uptake ENDOCYTOSIS NANOCARRIERS CHITOSAN Bioactive compounds
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Hydrocarbon distribution along the Soapaga thrust(Eastern Cordillera, Colombia) based on new strategic geochemistry samples
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作者 Eduardo A.Rossello Rolando Di Primio 《Acta Geochimica》 EI CAS CSCD 2022年第3期335-350,共16页
The Colombian Eastern Cordillera constitutes a region with potential for finding hydrocarbon reserves that are still under-explored, despite the existence of oil and tar sand production. The intense tectonic deformati... The Colombian Eastern Cordillera constitutes a region with potential for finding hydrocarbon reserves that are still under-explored, despite the existence of oil and tar sand production. The intense tectonic deformation affects the petroleum systems and increases exploration challenges due to the different generation, maturation, and entrapment conditions that they produce. Diverse geochemical analysis conducted on strategic samples determines that these are likely generated by the same anoxic marine source rock type. Two source rock samples we investigated are characterized by very different biomarker signals as compared to the tar sands and oil samples. Both samples are dominated by hopanes as compared to tri-and tetracyclic terpanes, with very low(Tibasosa Formation) to no(Chipaque Formation) extended tricyclic terpanes. The Soapaga Thrust, along which the analyzed samples are located, has exercised first-rate regional structural control of the distribution of hydrocarbons in the studied area. The uplift of their Mesozoic hanging wall produces intense erosion with sediment transport towards the eastern footwall forming the present infill of the Arcabuco basin. The kitchen areas were connected with the shallower entrapment sectors where excellent reservoir levels such as the Picacho Formation before the Soapaga Thrust movement. The high degree of biodegradation observed in the Picacho Fm. tar sands support early charge before the Soapaga thrust movement, and severe biodegradation following the thrust movement when hydrocarbon supply from the kitchen was interrupted. This work aims to contribute to a better understanding of the geochemical characteristics of the petroleum systems due to the action of the Soapaga Thrust. 展开更多
关键词 Hydrocarbon geochemistry Soapaga thrust Eastern Cordillera Colombia
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Response of saproxylic insect communities to logging history, tree species, stage of decay, and wood posture in the central Nearctic boreal forest
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作者 R.W.James Dennis Jay R.Malcolm +1 位作者 Sandy M.Smith M.Isabel Bellocq 《Journal of Forestry Research》 SCIE CAS CSCD 2018年第5期1365-1377,共13页
Saproxylic insect assemblages are essential functional components of forest ecosystems that can be affected by forest management.We used a split-plot ANOVA design to analyze differences in selected saproxylic insects... Saproxylic insect assemblages are essential functional components of forest ecosystems that can be affected by forest management.We used a split-plot ANOVA design to analyze differences in selected saproxylic insects(all arthropod orders and dipteran and parasitic hymenopteran families) emerging from dead wood of sites with different logging histories(horse-logged,mechanically-logged and unlogged),tree species(Populus and Picea),stage of decay(early-and late-decay stages) and posture(standing and downed logs) in the boreal forest of central Canada.No clear effects of logging history were seen for the studied taxa; however,interaction between logging history and other dead wood features was apparent.Cecidomyiidae consistently emerged more from Populus than from Picea dead wood.Most of the studied saproxylic families were more abundant in late-decay than in early-decay wood.Dipterans of the Cecidomyiidae,Ceratopogonidae,Empididae,Mycetophilidae and Sciaridae families,and hymenopterans of the Diapriidae and Ichneumonidae families were significantly more abundant in downed than in standing dead wood.In contrast,Mymaridae was most abundant in standing dead wood.Our study provides evidence that some insects at high taxonomic levels respond differently to dead wood quality,and this could inform future management strategies in the boreal forest for the conservation of saproxylic fauna and their ecological functions. 展开更多
关键词 Boreal forest Dead wood quality Forest harvesting High-level taxa Saproxylic insects
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Ecofriendly E-Nose Based in PLA and Only 0.3 wt%of CNTs
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作者 Laura Ribba Jonathan Cimadoro Silvia Goyanes 《Journal of Renewable Materials》 SCIE 2019年第4期355-363,共9页
In this work,conductive polymer nanocomposites were developed based on a biodegradable and biobased polymer(poly(lactic acid)),with the incorporation of only 0.3 wt%of carbon nanotubes(CNTs)to be used as volatile solv... In this work,conductive polymer nanocomposites were developed based on a biodegradable and biobased polymer(poly(lactic acid)),with the incorporation of only 0.3 wt%of carbon nanotubes(CNTs)to be used as volatile solvent sensors.The correct dispersion of the nanofiller was achieved thanks to a CNT non-covalent modification with an azo-dye(disperse orange 3)which allowed to reach the percolation for electric conduction in values as low as 0.3 wt%.The chemo-resistive properties of the developed sensors were investigated by exposure to organic vapors(ethanol,tetrahydrofuran and toluene)and water vapor,showing good selectivity.In addition,considering the manipulation to which the sensor will be exposed,wear resistance was characterized,finding that the incorporation of CNTs produced an increase in more than a 50%. 展开更多
关键词 Poly(lactic acid) carbon nanotubes sensor CPC organic solvent vapor DO3
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The impact of paralog genes:detection of copy number variation in spinal muscle atrophy patients
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作者 Sergio LAURITO Juan A.CUETO +1 位作者 Jimena PEREZ María ROQUé 《BIOCELL》 SCIE 2018年第3期87-91,共5页
Spinal muscular atrophy(SMA)is caused by dysfunction of the alpha motor neurons of the spinal cord.It is an autosomal recessive disease associated to the SMN1 gene,located in the subtelomeric region of 5q13.A paralog ... Spinal muscular atrophy(SMA)is caused by dysfunction of the alpha motor neurons of the spinal cord.It is an autosomal recessive disease associated to the SMN1 gene,located in the subtelomeric region of 5q13.A paralog SMN2 gene is located at the centromeric region of the same chromosome,which apparently originated by an ancestral inverted duplication occurring only in humans.The exon sequence differs in two nucleotides in exon 7 and exon 8,which leads to an SMN2 transcript that lacks exon 7 and results in a truncated protein.Part(10%)of the SMN2 transcripts avoids the splicing of exon 7 but most of the copies are dysfunctional.In a disease scenario,the more SMN2 copies the higher possibility to restore at least partly the effects of SMN1 deficiency.Some therapeutic approaches are being developed to increase the expression of SMN2.To determine the number of SMN1 and SMN2 copies,the methodology must distinguish accurately between both genes.In this work,we present the results obtained using multiplex ligation-dependent probe amplification(MLPA)in 60 SMA suspected patients/carriers derived from different regions of Argentina.In 32 of these DNA samples we found alterations in SMN1.Among these,16 presented a heterozygous deletion(carrier status)and 14 an homozygous deletion(patient status)in exon 7 and 8 of SMN1.In one case,exon 7 was found homozygously deleted but exon 8 presented a single copy,and in another case,exon 7 was found heterozygously deleted while exon 8 was normal.Almost half of the patients(7/15)presented a normal diploid number of SMN2 while the other half(8/15)presented an increased number.In this work we showed how a probe-based methodology such as MLPA was able to distinguish between the paralog genes and determine the amount of copies in DNA samples from suspected patients/carriers of SMA. 展开更多
关键词 SMA CNV MLPA Paralog gene
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NO-ARBITRAGE SYMMETRIES
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作者 Iván DEGANO Sebastián FERRANDO Alfredo GONZáLEZ 《Acta Mathematica Scientia》 SCIE CSCD 2022年第4期1373-1402,共30页
The no-arbitrage property is widely accepted to be a centerpiece of modern financial mathematics and could be considered to be a financial law applicable to a large class of(idealized) markets.This paper addresses the... The no-arbitrage property is widely accepted to be a centerpiece of modern financial mathematics and could be considered to be a financial law applicable to a large class of(idealized) markets.This paper addresses the following basic question:can one characterize the class of transformations that leave the law of no-arbitrage invariant?We provide a geometric formalization of this question in a non probabilistic setting of discrete time-the so-called trajectorial models.The paper then characterizes,in a local sense,the no-arbitrage symmetries and illustrates their meaning with a detailed example.Our context makes the result available to the stochastic setting as a special case. 展开更多
关键词 No arbitrage symmetry convexity preserving maps non-probabilistic markets
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Freely Available Tool(FAT)for automated quantification of lipid droplets in stained cells
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作者 DIEGO MASONE ALDANA DGOJANOVICH +3 位作者 YESICA R.FRONTINI-LOPEZ SAMANTA DEL VELIZ MARINA UHART DIEGO M.BUSTOS 《BIOCELL》 SCIE 2017年第2期55-58,共4页
In this study,we propose an automatic procedure for digital image processing.We describe a method that can efficiently quantify and characterize lipid droplets distributions in different cell types in culture.Prospect... In this study,we propose an automatic procedure for digital image processing.We describe a method that can efficiently quantify and characterize lipid droplets distributions in different cell types in culture.Prospectively,the lipid droplets detection method described in this work could be applied to static or time-lapse data,collected with a simple visible light or fluorescence microscopy equipment.Fully automated algorithms were implemented in Octave,a freely available scientific package. 展开更多
关键词 ADIPOGENESIS 3T3-L1 cells human stem cells automatic image processing
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