Four sites were selected in a salt marsh in the Bahia Blanca Estuary （Argentina）： （1） low marsh （flooded by the tide twice daily） vegetated by S. alterniflora; （2） non-vegetated low marsh; （3） high marsh （...Four sites were selected in a salt marsh in the Bahia Blanca Estuary （Argentina）： （1） low marsh （flooded by the tide twice daily） vegetated by S. alterniflora; （2） non-vegetated low marsh; （3） high marsh （flooded only in spring tides） vegetated by S. alterniflora; （4） non-vegetated high marsh. The pH and Eh were measured in sediments, while dissolved nutrients （ammonium, nitrate, nitrite and phosphate） and particulate organic matter （POM） were determined in pore water, pH （6.2-8.7） was only affected by vegetation in low areas. Eh （from -300 to 250 mV） was lower at low sites than at high ones; in the latter, the values were higher in the non-vegetated sediments. The POM concentration was greater in the high marsh than in the low marsh, with no effect of vegetation. Ammonium was the most abundant nitrogen nutrient species in pore water, except in the non-vegetated high marsh where nitrate concentration was higher. All nitrogen nutrients were affected by both flooding and vegetation. Phosphate was always present in pore water at all sites throughout the year and its concentration varied within narrow limits, with no effect of flooding and greater values always at non-vegetated sites. Our results showed that the variability of the pore water composition within the marsh is greater than the temporal variation, meaning that both tidal flooding and vegetation are important in the dynamics of nutrients and organic matter in the sediment pore water.展开更多
Tharsis is the most prominent volcanic province on Mars,yet the compositions of lava flows and how composition relates to the development of Tharsis are poorly known.Most of Tharsis is covered with air-fall dust,which...Tharsis is the most prominent volcanic province on Mars,yet the compositions of lava flows and how composition relates to the development of Tharsis are poorly known.Most of Tharsis is covered with air-fall dust,which inhibits spectroscopic determination of lava mineralogy.The Syria-Thaumasia Block(STB)is a complex tectono-volcanic province closely related to the Tharsis bulge.The lava plains of STB have different emplacement ages,which provide an opportunity to examine whether magma composition changed with the evolution of Tharsis.In this study,we assessed the lava plains using Thermal Emission Spectrometer(TES)data.Using derived physical properties,we targeted dust-free regions from four different-aged geological units'surfaces and determined the mineralogical composition by modeling the average TES surface spectrum from each of the four surfaces.All units have similar mineralogy but the younger two units have elevated abundance of high-SiO2phases.The spatial distribution of wrinkle ridges indicates lava plains of unit HNr(older ridged plains material)and Hr(younger ridged plains material)were emplaced before the rise of Tharsis,whereas Hsl(flows of lower member)and Hsu(upper member)were emplaced after Tharsis uplift was initiated.We show that the magma composition differed in the lava plains of STB after the uplift of Tharsis.This study further characterizes early martian magma composition and evolution.展开更多
Dune barrier systems represent highly sought-after coastal landscapes for tourism and urban development around the world.However,a century ago,they were considered hazardous environments due to their great dynamic nat...Dune barrier systems represent highly sought-after coastal landscapes for tourism and urban development around the world.However,a century ago,they were considered hazardous environments due to their great dynamic nature.As a result,stabilization practices were considered necessary.The systematic introduction of fast-growing exotic trees helped stabilize the sand,making it easier for tourism urbanization to take place,but also leading to erosion processes.This paper aims to assess long-term changes in vegetation cover over a large temperate barrier in Argentina.This complex region includes urban resorts,afforestation zones,and protected areas.A GIS-based geospatial analysis was conducted using a large satellite database(>350 images),and the future evolution of the vegetation was modeled.The results revealed two primary spatiotemporal patterns associated with a gradual expansion of vegetation cover,accompanied by a concurrent reduction in sandy areas.In 1986,the dune area comprised 75%more surface than vegetation,whereas in 2021,it represented 60%less than vegetation.Furthermore,the 2050 scenario suggests a potential 40%reduction of dunes in certain areas.It is necessary to enhance management actions aimed at maintaining dune mobility and ensuring local and regional sediment balance.Long-term management strategies must focus on restoring native plant communities and controlling invasive species,and avoiding new dune fixation initiatives based on the introduction of exotic species.展开更多
This paper argues that in an era of accelerating climate change and rising sea levels,what truly matters is not merely the marine structure itself,but the foresight and adaptability embedded in its conception.As globa...This paper argues that in an era of accelerating climate change and rising sea levels,what truly matters is not merely the marine structure itself,but the foresight and adaptability embedded in its conception.As global urbanization intensifies along coastlines,and as storms grow stronger and ecosystems degrade,there is an urgent need for transformative approaches to ocean engineering and design.We introduce Terrestrial Education,an interdisciplinary framework that moves beyond conventional sustainability models by integrating ecological intelligence,regenerative systems thinking,and advanced technologies.Unlike traditional approaches that focus on minimizing harm,Terrestrial Education emphasizes active ecological restoration,socio-technical evolution,and planetary stewardship.Drawing on lessons from space exploration,such as closed-loop life support systems,autonomous environmental management,and modular habitat design,we demonstrate how these principles can inspire resilient marine infrastructures,including floating platforms,submerged laboratories,and biointegrated offshore structures.These designs are envisioned not only for their physical durability but also for their capacity to regenerate ecosystems and foster meaningful human interaction with marine environments.The paper highlights key priorities such as adaptability to climate extremes,energy efficiency through marine renewables,and environmental integration using biomimetic materials.By aligning with the Sustainable Development Goals of the blue economy,Terrestrial Education offers a future-oriented model that harmonizes environmental,technological,and economic objectives.Ultimately,this framework provides a conceptual and operational foundation for reimagining marine structures as catalysts for innovation,educational transformation,and resilient planetary futures in the climate era.展开更多
Interest in the use of cellulose nanomaterial’s continues to grow,both in research and industry,not only due to the abundance of raw materials,low toxicity and sustainability,but also due to the attractive physical a...Interest in the use of cellulose nanomaterial’s continues to grow,both in research and industry,not only due to the abundance of raw materials,low toxicity and sustainability,but also due to the attractive physical and chemical properties that make nanocelluloses useful for a wide range of end-use applications.Among the large number of potential uses,and nanocelluloses modification and processing strategies,the chosen topic of this review focuses exclusively on plant-derived cellulose microfibers/nanofibers(CNF)and cellulose nanocrystals(CNC)processed into 2D structures—nanopapers and nanofilms—fabricated as self-standing films or applied as coatings.The end uses considered are:combinationwith standard papers and cardboards for packaging,mendingmaterial for the conservation and protection of cellulosic heritage artifacts,and component-parts of complex designs of functional devices for energy harvesting and storage.In these contexts,nanocelluloses provide high mechanical and ecofriendly properties,transparency and tunable haze,as well as flexibility/bendability in the resulting films.All these characteristics make them extremely attractive to a market seeking for sustainable,light weight and low cost raw materials for the production of goods.General perspectives on the current advantages and disadvantages of using CNF and CNC in the selected areas are also reviewed.展开更多
Cytokinins are plant hormones that are essential for plant growth and development and are involved in a variety of processes.They are synthesized by the modification of adenine with an isoprenoid chain,resulting in cy...Cytokinins are plant hormones that are essential for plant growth and development and are involved in a variety of processes.They are synthesized by the modification of adenine with an isoprenoid chain,resulting in cytokinins such as isopentenyladenine and zeatin.The levels of these hormones are regulated by conjugation,degradation and oxidation processes that modulate their activity.Cytokinins are perceived by cells through specific receptors that,when activated,trigger signaling cascades responsible for regulating the expression of genes critical for development.In addition,cytokinins interact with other hormones,such as auxins,to coordinate plant growth and architecture.They are transported by the xylem and phloem,allowing them to be distributed to different parts of the plant and to regulate processes such as cell division,morphogenesis and inhibition of leaf senescence,thereby prolonging the vegetative phase.Cytokinins also play a role in plant responses to biotic and abiotic stresses.They influence the expression of defense genes against pathogens and pests and adjust plant metabolism and growth in response to adverse conditions such as drought and salinity.Cytokinins interact in an integrated manner with other stress hormones,such as abscisic acid and ethylene,to coordinate plant responses to environmental challenges.In agriculture,the manipulation of cytokinins,whether by external application or genetic modification,shows great potential for increasing crop yields and improving plant resistance to stress.Advances in molecular biology and gene editing offer new opportunities to precisely modify these functions.This review elucidates recent research on cytokinins,covering their mechanisms of action,interactions with other hormones,and applications in agriculture.展开更多
Male fiddler crabs own an enlarged claw which is a weapon and an ornament.The enlargement of this claw begins from the juvenile stage and continues throughout life.Males may voluntarily lose(i.e.,autotomize)this claw....Male fiddler crabs own an enlarged claw which is a weapon and an ornament.The enlargement of this claw begins from the juvenile stage and continues throughout life.Males may voluntarily lose(i.e.,autotomize)this claw.After several molts males may regenerate a new claw,called leptochelous,which acquires a similar length but a lower muscle mass area than the original one,called brachychelous.In some species,regenerated claws develop permanently as leptochelous,the population having 2 discrete claw morphologies.Other species present morphological variations with leptochelous and brachychelous being 2 ends of a continuum.In the species Leptuca uruguayensis,we studied the morphological variation of this enlarged claw,whether it may be caused by its regeneration at different male sizes,and its consequences on mating success.We found that claws could not be discriminated as discrete morphs,suggesting a morphological continuum from brachychelous to leptochelous.Regenerated claws in the laboratory were initially small and proportional to body size,although a field experiment confirmed that claw size is recovered after several molts.Morphological variation may be caused by energetic limitations where males of different sizes must differently trade-off between restitution of claw length(ornament function)or claw muscle area(weapon function).Fiddler crabs use 2 mating tactics with different levels of female choice.However,regardless of the mating tactic,leptochelous males were at a disadvantage at high densities,although not at low densities,suggesting that the consequences of autotomy and regeneration on mating success may depend on the social context.展开更多
In this study,the effect of Tin(Sn)addition on the microstructure,mechanical properties,and wear resistance of pure magnesium(Mg)was examined.Mg-Sn alloys were synthesized using stir casting technique with Sn concentr...In this study,the effect of Tin(Sn)addition on the microstructure,mechanical properties,and wear resistance of pure magnesium(Mg)was examined.Mg-Sn alloys were synthesized using stir casting technique with Sn concentrations of 2.5%,5%,and 7.5% by weight.The specimens were prepared as per ASTM standards for their evaluation.Higher Sn concentrations result in a reduced volume fraction of the eutectic phase,while Mg_(2)Sn precipitates are observed in alloys with 5% or more Sn.Scanning electron microscopy(SEM)analysis of the Mg-7.5wt.%Sn alloy reveals the presence of Mg(OH)_(2),with X-ray diffraction(XRD)confirming an oxygen content of 18% by weight.The addition of Sn minimizes casting porosity,enhancing the quality of the alloys.The findings demonstrate a positive correlation between increasing Sn content and enhanced strength and wear resistance.The Mg-7.5wt.%Sn alloy exhibits significantly enhanced tensile properties attributed to grain refinement and the formation of well-defined grain boundaries compared to alloys with lower Sn additions(2.5% and 5%),although a slight reduction in microhardness is observed.Tribological evaluation indicates reduced wear and friction,suggesting better surface performance.This research underscores the complex interplay between Sn content,microstructural evolution,and the resulting mechanical and tribological performance of Mg-Sn alloys.展开更多
In plants,the ubiquitin–proteasome system(UPS)plays a central role in hormonal regulation,including the action of the phytohormone auxin,which orchestrates numerous aspects of growth and development.Auxin modulates r...In plants,the ubiquitin–proteasome system(UPS)plays a central role in hormonal regulation,including the action of the phytohormone auxin,which orchestrates numerous aspects of growth and development.Auxin modulates redox metabolism and promotes the accumulation of nitric oxide(NO)in various tissues and physiological contexts.NO functions as a redox signaling molecule,exerting its effects in part through the reversible oxidation of cysteine residues via a post-translational modification known as S-nitrosylation.Recent findings highlight a dynamic interplay between S-nitrosylation and the ubiquitination machinery,shaping critical aspects of auxin-mediated plant responses.In this review,we summarize current knowledge on redox regulation of UPS components involved in auxinmediated pathways and propose new perspectives on the integration of hormonal and redox signaling in plants.We describe and discuss the complexity of the latest evidence supporting the role of NO as a second messenger in auxin signaling,with S-nitrosylation acting as a regulatory mechanism that fine-tunes the UPS to control developmental outcomes.We focused on the direct effects of NO that include S-nitrosylation of specific cysteine residues of substrates,adaptors,and substrate receptors belonging to different CULLIN1-and CULLIN4-based E3 ubiquitin ligase complexes.展开更多
Financial time series have been analyzed with a wide variety of models and approaches,some of which can forecast with great accuracy.However,most of these models,especially the machine learning ones,cannot show additi...Financial time series have been analyzed with a wide variety of models and approaches,some of which can forecast with great accuracy.However,most of these models,especially the machine learning ones,cannot show additional information for the decision maker or the financial analyst.The notion of causality is a concept that provides a more complete understanding of a problem beyond improved forecasts.In this study,we propose integrating the treatment/control concept of causality into a forecasting framework to better predict financial time series.Our results show that the proposed methodology outperforms classic econometric approaches such as ARIMA and Random Walk,as well as machine learning approaches without the proposed methodology.This improvement is statistically significant,as indicated by the Model Confidence Set test in the complete test set and quarterly analysis.展开更多
Chaetoceros is a species-diverse genus of marine diatoms.The section Chaetoceros,recognized for the presence of numerous chloroplasts in both cell body and setae,is a common group of marine phytoplankton containing so...Chaetoceros is a species-diverse genus of marine diatoms.The section Chaetoceros,recognized for the presence of numerous chloroplasts in both cell body and setae,is a common group of marine phytoplankton containing some species,which may cause harm to marine organisms due to the robust setae.Modern taxonomic studies combining morphological and molecular data are still limited for the section Chaetoceros.To explore the diversity of the section Chaetoceros,monoclonal strains were established from the South China Sea and two novel species are described here,C.tetracarina sp.nov.and C.dicrinis sp.nov.Chaetoceros tetracarina is unique by the rimoportula on the anterior valve having four basal ridges supporting the external tube,whereas the other rimoportulae in the same chains or the one on the posterior valve for single cells each only possess a long external tube and lack basal ridges.Chaetoceros dicrinis is solitary and characterized by the symmetrical extending of the two setae on the same valve under light microscope(LM).The phylogenetic results show the presence of several groups within the section Chaetoceros.Chaetoceros tetracarina was sister to C.cf.pseudodichaeta,but differed by 33 and 46 bps in ribosomal large-subunit(LSU)and small-subunit(SSU)sequences respectively.The most closely-related species of C.dicrinis was C.denticulatus,but they were distinctly different morphologically,differing by 3 and 2 bps in LSU and SSU sequences respectively.This study provides new findings to understand the diversity of section Chaetoceros;however the inner relationships within this section remain largely unresolved.展开更多
The variability of the sea surface salinity measurements provided by the Soil Moisture and Ocean Salinity mission reveals the presence of a local salinity maximum(a salty tongue)in the northwestern tropical Atlantic.T...The variability of the sea surface salinity measurements provided by the Soil Moisture and Ocean Salinity mission reveals the presence of a local salinity maximum(a salty tongue)in the northwestern tropical Atlantic.The sea surface salinity positive anomaly starts increasing in July,reaches its maximum in January,and then disappears.The local maximum of salinity appears in the late boreal autumn/winter,when the Amazon discharge is minimal and the salty water from the South Atlantic is transported by the North Brazil Current along the shelf break across the equator.The authors validate the satellite observations in this area and assess the vertical structure of the salinity maximum by using in situ measurements and an in situ-interpolated product.展开更多
In froth flotation,overall recovery of the floatable particles consists of true recovery and recovery by entrainment,where entrainment refers to the non-selective recovery of particles in the concentrate.To understand...In froth flotation,overall recovery of the floatable particles consists of true recovery and recovery by entrainment,where entrainment refers to the non-selective recovery of particles in the concentrate.To understand and optimize the flotation process with regard to process conditions,it is essential to distinguish true flotation recovery from overall recovery.The established methods rely on tailored flotation experiments,unrealistic flotation conditions,or using external tracers which can be different in density and crystal structure to the mineral(s) of interest.This study presents an approach to utilize naturally occuring suitable tracers to estimate the entrainment component from overall recovery of individual particles by establishing a relationship between their settling velocity coefficient and recovery probability.Recovery probabilities of individual particles are computed using particle-based separation modelling.The approach is demonstrated for a copper ore,where naturally occurring rutile was used as the tracer to determine the entrained component of the overall recovery of chalcopyrite particles.Laboratory flotation experiments revealed that entrainment accounted for up to 6% of the overall recovery probability of fully liberated chalcopyrite particles in the fine size fractions.This approach provides a practical method for entrainment correction enabling a more accurate evaluation of true flotation recovery.展开更多
Through the analysis of representative samples of field galaxies,both local(z~0.027)and distant(z~0.7),we explore the barred galaxy fraction and its dependence on stellar mass,color,and morphology,aiming to understand...Through the analysis of representative samples of field galaxies,both local(z~0.027)and distant(z~0.7),we explore the barred galaxy fraction and its dependence on stellar mass,color,and morphology,aiming to understand the evolution of these structural components through cosmic time.To this end,two complementary bar detection techniques were employed:elliptical isophote fitting and two-dimensional Fourier analysis,both applied to deep optical images.The observational samples were drawn from previously established and calibrated catalogs to ensure a homogeneous selection in stellar mass,enabling a robust comparison between local galaxies(z~0.027)and those in the distant Universe(z~0.7).This study systematically applies both isophotal fitting and Fourier decomposition across a wide redshift range,offering a comprehensive view of the evolution of bar incidence as a function of stellar mass and morphology.The results indicate that the fraction of barred galaxies is significantly higher in the local Universe than at earlier epochs,particularly among spiral galaxies.Furthermore,a clear correlation is observed between the presence of bars and stellar mass,especially in the high-mass regime(log(M_*/M☉)>10.5).In distant galaxies,this fraction is lower across all mass ranges,which may be related to more active dynamical processes.Overall,the findings reinforce the idea that stellar bars emerge as a consequence of dynamical cooling and the progressive stabilization of galactic disks,playing a key role in gas transport and the internal structural evolution of galaxies from z~1 to the present day.展开更多
Cetaceans include the largest animals ever to have lived onearth and are uniparous(producing a single calf at each birth)across the infraorder.However,instances of multiple fetuseshave been observed naturally among un...Cetaceans include the largest animals ever to have lived onearth and are uniparous(producing a single calf at each birth)across the infraorder.However,instances of multiple fetuseshave been observed naturally among uniparous mammals,including cetaceans.Despite this,there is no known documented case of twins in cetaceans successfully carried to termin the wild(Perrin and Donovan 1984),and if such casesexist,they would be diffcult to detect.展开更多
Sickle cell anemia (SCA) is a prevalent genetic disorder primarily affecting individuals of African descent and populations in malaria-endemic regions, with significant global public health implications. Sickle cell c...Sickle cell anemia (SCA) is a prevalent genetic disorder primarily affecting individuals of African descent and populations in malaria-endemic regions, with significant global public health implications. Sickle cell crises are their most common acute complication, characterized by episodes of intense pain and systemic manifestations that impair quality of life and impose a high healthcare burden. We present the case of a 19-year-old male diagnosed with SCA since the age of two, who developed a sickle cell crisis precipitated by right basal pneumonia. The patient exhibited sudden-onset, cyclic lumbar pain with progressive dyspnea. Initial management included multimodal pain control, volume optimization, and targeted antimicrobial therapy to achieve clinical stabilization. This case underscores the importance of a comprehensive approach to managing sickle cell crises, addressing both symptomatic relief and the prevention and treatment of complications. It also highlights the need for public health strategies promoting early diagnosis, access to disease-modifying therapies such as hydroxyurea, and interdisciplinary follow-up to mitigate the socioeconomic and clinical impact of SCA.展开更多
BACKGROUND Hypoxia in oral cancer promotes tumoral invasion by inducing epithelial-mesenchymal transition,leading to aggressive tumor progression.AIM To characterize the expression of hypoxia-inducible factor 1-alpha(...BACKGROUND Hypoxia in oral cancer promotes tumoral invasion by inducing epithelial-mesenchymal transition,leading to aggressive tumor progression.AIM To characterize the expression of hypoxia-inducible factor 1-alpha(HIF-1α)at the invasive tumor front(ITF)in comparison to tumor islands(TI)in oral squamous cell carcinoma(OSCC)and to explore its relationship with E-cadherin and Vimentin expression.METHODS Thirty-eight cases of OSCC and five cases of normal oral mucosa(NOM)were included in this study.The ITF was identified based on the region and immune expression of AE1/AE3.Immunohistochemistry was performed to assess the expression of HIF-1α,Vimentin,and E-cadherin.The immunostaining was analyzed using an immunoreactive score,and the results were illustrated using immunofluorescence.RESULTS HIF-1αexpression was significantly higher in the TI region compared to the ITF region(P=0.0134).Additionally,a significant difference was observed between TI and NOM(P=0.0115).In the ITF regions,HIF-1αexpression showed a significant correlation with Vimentin expression,with higher levels of HIF-1αassociated with increased Vimentin expression(P=0.017).CONCLUSION Based on the results of this study,HIF-1αappears to play a distinct role in OSCC tumor progression,underscoring the importance of exploring hypoxia-driven changes in cellular phenotype at the ITF of OSCC.Further research is needed to better understand their impact on OSCC prognosis.展开更多
基金supported by Agencia Nacional de Promoción Científica y Tecnológica (PICT N°0945/2006) of Argentina
文摘Four sites were selected in a salt marsh in the Bahia Blanca Estuary （Argentina）： （1） low marsh （flooded by the tide twice daily） vegetated by S. alterniflora; （2） non-vegetated low marsh; （3） high marsh （flooded only in spring tides） vegetated by S. alterniflora; （4） non-vegetated high marsh. The pH and Eh were measured in sediments, while dissolved nutrients （ammonium, nitrate, nitrite and phosphate） and particulate organic matter （POM） were determined in pore water, pH （6.2-8.7） was only affected by vegetation in low areas. Eh （from -300 to 250 mV） was lower at low sites than at high ones; in the latter, the values were higher in the non-vegetated sediments. The POM concentration was greater in the high marsh than in the low marsh, with no effect of vegetation. Ammonium was the most abundant nitrogen nutrient species in pore water, except in the non-vegetated high marsh where nitrate concentration was higher. All nitrogen nutrients were affected by both flooding and vegetation. Phosphate was always present in pore water at all sites throughout the year and its concentration varied within narrow limits, with no effect of flooding and greater values always at non-vegetated sites. Our results showed that the variability of the pore water composition within the marsh is greater than the temporal variation, meaning that both tidal flooding and vegetation are important in the dynamics of nutrients and organic matter in the sediment pore water.
基金supported by China Postdoctoral Science Foundation (Grant No. 2013M540614)the Postdoctoral International Exchange Project+1 种基金the National Natural Science Foundation of China (Grant No. 41373066)the Specialized Research Fund for the Doctoral Program of Higher Education (SRFDP) (Grant No. 20130145130001)
文摘Tharsis is the most prominent volcanic province on Mars,yet the compositions of lava flows and how composition relates to the development of Tharsis are poorly known.Most of Tharsis is covered with air-fall dust,which inhibits spectroscopic determination of lava mineralogy.The Syria-Thaumasia Block(STB)is a complex tectono-volcanic province closely related to the Tharsis bulge.The lava plains of STB have different emplacement ages,which provide an opportunity to examine whether magma composition changed with the evolution of Tharsis.In this study,we assessed the lava plains using Thermal Emission Spectrometer(TES)data.Using derived physical properties,we targeted dust-free regions from four different-aged geological units'surfaces and determined the mineralogical composition by modeling the average TES surface spectrum from each of the four surfaces.All units have similar mineralogy but the younger two units have elevated abundance of high-SiO2phases.The spatial distribution of wrinkle ridges indicates lava plains of unit HNr(older ridged plains material)and Hr(younger ridged plains material)were emplaced before the rise of Tharsis,whereas Hsl(flows of lower member)and Hsu(upper member)were emplaced after Tharsis uplift was initiated.We show that the magma composition differed in the lava plains of STB after the uplift of Tharsis.This study further characterizes early martian magma composition and evolution.
基金supported by the Ministry of Science,Technology and Innovation of Argentina trough the project“Topografía,escurrimiento superficial y monitoreo de playas en el Partido de Villa Gesell,provincia de Buenos Aires”(Impact.AR N°106-RESOL-2022-224-APN-SACT#MCT)by the Nacional Council of Scientific and Technical Research(CONICET)through the project“Impactos de la reversión del nivel del mar en Buenos Aires,Argentina”(PIP 21/2311220200100041CO-RESOL-2021-1639-APN-DIR#CONICET)。
文摘Dune barrier systems represent highly sought-after coastal landscapes for tourism and urban development around the world.However,a century ago,they were considered hazardous environments due to their great dynamic nature.As a result,stabilization practices were considered necessary.The systematic introduction of fast-growing exotic trees helped stabilize the sand,making it easier for tourism urbanization to take place,but also leading to erosion processes.This paper aims to assess long-term changes in vegetation cover over a large temperate barrier in Argentina.This complex region includes urban resorts,afforestation zones,and protected areas.A GIS-based geospatial analysis was conducted using a large satellite database(>350 images),and the future evolution of the vegetation was modeled.The results revealed two primary spatiotemporal patterns associated with a gradual expansion of vegetation cover,accompanied by a concurrent reduction in sandy areas.In 1986,the dune area comprised 75%more surface than vegetation,whereas in 2021,it represented 60%less than vegetation.Furthermore,the 2050 scenario suggests a potential 40%reduction of dunes in certain areas.It is necessary to enhance management actions aimed at maintaining dune mobility and ensuring local and regional sediment balance.Long-term management strategies must focus on restoring native plant communities and controlling invasive species,and avoiding new dune fixation initiatives based on the introduction of exotic species.
文摘This paper argues that in an era of accelerating climate change and rising sea levels,what truly matters is not merely the marine structure itself,but the foresight and adaptability embedded in its conception.As global urbanization intensifies along coastlines,and as storms grow stronger and ecosystems degrade,there is an urgent need for transformative approaches to ocean engineering and design.We introduce Terrestrial Education,an interdisciplinary framework that moves beyond conventional sustainability models by integrating ecological intelligence,regenerative systems thinking,and advanced technologies.Unlike traditional approaches that focus on minimizing harm,Terrestrial Education emphasizes active ecological restoration,socio-technical evolution,and planetary stewardship.Drawing on lessons from space exploration,such as closed-loop life support systems,autonomous environmental management,and modular habitat design,we demonstrate how these principles can inspire resilient marine infrastructures,including floating platforms,submerged laboratories,and biointegrated offshore structures.These designs are envisioned not only for their physical durability but also for their capacity to regenerate ecosystems and foster meaningful human interaction with marine environments.The paper highlights key priorities such as adaptability to climate extremes,energy efficiency through marine renewables,and environmental integration using biomimetic materials.By aligning with the Sustainable Development Goals of the blue economy,Terrestrial Education offers a future-oriented model that harmonizes environmental,technological,and economic objectives.Ultimately,this framework provides a conceptual and operational foundation for reimagining marine structures as catalysts for innovation,educational transformation,and resilient planetary futures in the climate era.
基金funded by Consejo Nacional de Investigaciones Cientificas y Tecnicas(CONICET,Argentina),grant number PIP 0991by Universidad Nacional de Mar del Plata(UNMdP,Argentina),grant number 15/G686-ING690/23.
文摘Interest in the use of cellulose nanomaterial’s continues to grow,both in research and industry,not only due to the abundance of raw materials,low toxicity and sustainability,but also due to the attractive physical and chemical properties that make nanocelluloses useful for a wide range of end-use applications.Among the large number of potential uses,and nanocelluloses modification and processing strategies,the chosen topic of this review focuses exclusively on plant-derived cellulose microfibers/nanofibers(CNF)and cellulose nanocrystals(CNC)processed into 2D structures—nanopapers and nanofilms—fabricated as self-standing films or applied as coatings.The end uses considered are:combinationwith standard papers and cardboards for packaging,mendingmaterial for the conservation and protection of cellulosic heritage artifacts,and component-parts of complex designs of functional devices for energy harvesting and storage.In these contexts,nanocelluloses provide high mechanical and ecofriendly properties,transparency and tunable haze,as well as flexibility/bendability in the resulting films.All these characteristics make them extremely attractive to a market seeking for sustainable,light weight and low cost raw materials for the production of goods.General perspectives on the current advantages and disadvantages of using CNF and CNC in the selected areas are also reviewed.
基金funded by Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior(CAPES)[Funding Code 001],CAPES/BRASIL PDPG-POSDOC No.2930/2022.Conselho Nacional de Desenvolvimento Cientifico e Tecnologico(CNPq)Fundacao de Amparo a Pesquisa do Estado de Minas Gerais(FAPEMIG)[BPD-00571-22].
文摘Cytokinins are plant hormones that are essential for plant growth and development and are involved in a variety of processes.They are synthesized by the modification of adenine with an isoprenoid chain,resulting in cytokinins such as isopentenyladenine and zeatin.The levels of these hormones are regulated by conjugation,degradation and oxidation processes that modulate their activity.Cytokinins are perceived by cells through specific receptors that,when activated,trigger signaling cascades responsible for regulating the expression of genes critical for development.In addition,cytokinins interact with other hormones,such as auxins,to coordinate plant growth and architecture.They are transported by the xylem and phloem,allowing them to be distributed to different parts of the plant and to regulate processes such as cell division,morphogenesis and inhibition of leaf senescence,thereby prolonging the vegetative phase.Cytokinins also play a role in plant responses to biotic and abiotic stresses.They influence the expression of defense genes against pathogens and pests and adjust plant metabolism and growth in response to adverse conditions such as drought and salinity.Cytokinins interact in an integrated manner with other stress hormones,such as abscisic acid and ethylene,to coordinate plant responses to environmental challenges.In agriculture,the manipulation of cytokinins,whether by external application or genetic modification,shows great potential for increasing crop yields and improving plant resistance to stress.Advances in molecular biology and gene editing offer new opportunities to precisely modify these functions.This review elucidates recent research on cytokinins,covering their mechanisms of action,interactions with other hormones,and applications in agriculture.
基金funded by the Agencia Nacional de Promoción Científica y Tecnológica(PICT-2019-2385)Consejo Nacional de Investigaciones Científicas y Técnicas(PIP-11220200102466CO)Universidad Nacional de Mar del Plata(EXA953/20).
文摘Male fiddler crabs own an enlarged claw which is a weapon and an ornament.The enlargement of this claw begins from the juvenile stage and continues throughout life.Males may voluntarily lose(i.e.,autotomize)this claw.After several molts males may regenerate a new claw,called leptochelous,which acquires a similar length but a lower muscle mass area than the original one,called brachychelous.In some species,regenerated claws develop permanently as leptochelous,the population having 2 discrete claw morphologies.Other species present morphological variations with leptochelous and brachychelous being 2 ends of a continuum.In the species Leptuca uruguayensis,we studied the morphological variation of this enlarged claw,whether it may be caused by its regeneration at different male sizes,and its consequences on mating success.We found that claws could not be discriminated as discrete morphs,suggesting a morphological continuum from brachychelous to leptochelous.Regenerated claws in the laboratory were initially small and proportional to body size,although a field experiment confirmed that claw size is recovered after several molts.Morphological variation may be caused by energetic limitations where males of different sizes must differently trade-off between restitution of claw length(ornament function)or claw muscle area(weapon function).Fiddler crabs use 2 mating tactics with different levels of female choice.However,regardless of the mating tactic,leptochelous males were at a disadvantage at high densities,although not at low densities,suggesting that the consequences of autotomy and regeneration on mating success may depend on the social context.
文摘In this study,the effect of Tin(Sn)addition on the microstructure,mechanical properties,and wear resistance of pure magnesium(Mg)was examined.Mg-Sn alloys were synthesized using stir casting technique with Sn concentrations of 2.5%,5%,and 7.5% by weight.The specimens were prepared as per ASTM standards for their evaluation.Higher Sn concentrations result in a reduced volume fraction of the eutectic phase,while Mg_(2)Sn precipitates are observed in alloys with 5% or more Sn.Scanning electron microscopy(SEM)analysis of the Mg-7.5wt.%Sn alloy reveals the presence of Mg(OH)_(2),with X-ray diffraction(XRD)confirming an oxygen content of 18% by weight.The addition of Sn minimizes casting porosity,enhancing the quality of the alloys.The findings demonstrate a positive correlation between increasing Sn content and enhanced strength and wear resistance.The Mg-7.5wt.%Sn alloy exhibits significantly enhanced tensile properties attributed to grain refinement and the formation of well-defined grain boundaries compared to alloys with lower Sn additions(2.5% and 5%),although a slight reduction in microhardness is observed.Tribological evaluation indicates reduced wear and friction,suggesting better surface performance.This research underscores the complex interplay between Sn content,microstructural evolution,and the resulting mechanical and tribological performance of Mg-Sn alloys.
基金supported by grants from CONICET(PIP 0237 to MCT)Agencia Nacional de Promoción Científica y Tecnológica(ANPCYT,grant PICT-2020-0178 to MJI)Universidad Nacional deMar del Plata(EXA 1217/24 and 1179/24 to MCT).
文摘In plants,the ubiquitin–proteasome system(UPS)plays a central role in hormonal regulation,including the action of the phytohormone auxin,which orchestrates numerous aspects of growth and development.Auxin modulates redox metabolism and promotes the accumulation of nitric oxide(NO)in various tissues and physiological contexts.NO functions as a redox signaling molecule,exerting its effects in part through the reversible oxidation of cysteine residues via a post-translational modification known as S-nitrosylation.Recent findings highlight a dynamic interplay between S-nitrosylation and the ubiquitination machinery,shaping critical aspects of auxin-mediated plant responses.In this review,we summarize current knowledge on redox regulation of UPS components involved in auxinmediated pathways and propose new perspectives on the integration of hormonal and redox signaling in plants.We describe and discuss the complexity of the latest evidence supporting the role of NO as a second messenger in auxin signaling,with S-nitrosylation acting as a regulatory mechanism that fine-tunes the UPS to control developmental outcomes.We focused on the direct effects of NO that include S-nitrosylation of specific cysteine residues of substrates,adaptors,and substrate receptors belonging to different CULLIN1-and CULLIN4-based E3 ubiquitin ligase complexes.
基金ANID for supporting the Fondecyt project 1200555.
文摘Financial time series have been analyzed with a wide variety of models and approaches,some of which can forecast with great accuracy.However,most of these models,especially the machine learning ones,cannot show additional information for the decision maker or the financial analyst.The notion of causality is a concept that provides a more complete understanding of a problem beyond improved forecasts.In this study,we propose integrating the treatment/control concept of causality into a forecasting framework to better predict financial time series.Our results show that the proposed methodology outperforms classic econometric approaches such as ARIMA and Random Walk,as well as machine learning approaches without the proposed methodology.This improvement is statistically significant,as indicated by the Model Confidence Set test in the complete test set and quarterly analysis.
基金Supported by the National Key Research and Development Program of China(No.2022 YFC 3105201)the National Natural Science Foundation of China(No.32170206)the Joint Fund of National Natural Science Foundation of China and NSFC-Shandong Joint Key Project(No.U 2106205)。
文摘Chaetoceros is a species-diverse genus of marine diatoms.The section Chaetoceros,recognized for the presence of numerous chloroplasts in both cell body and setae,is a common group of marine phytoplankton containing some species,which may cause harm to marine organisms due to the robust setae.Modern taxonomic studies combining morphological and molecular data are still limited for the section Chaetoceros.To explore the diversity of the section Chaetoceros,monoclonal strains were established from the South China Sea and two novel species are described here,C.tetracarina sp.nov.and C.dicrinis sp.nov.Chaetoceros tetracarina is unique by the rimoportula on the anterior valve having four basal ridges supporting the external tube,whereas the other rimoportulae in the same chains or the one on the posterior valve for single cells each only possess a long external tube and lack basal ridges.Chaetoceros dicrinis is solitary and characterized by the symmetrical extending of the two setae on the same valve under light microscope(LM).The phylogenetic results show the presence of several groups within the section Chaetoceros.Chaetoceros tetracarina was sister to C.cf.pseudodichaeta,but differed by 33 and 46 bps in ribosomal large-subunit(LSU)and small-subunit(SSU)sequences respectively.The most closely-related species of C.dicrinis was C.denticulatus,but they were distinctly different morphologically,differing by 3 and 2 bps in LSU and SSU sequences respectively.This study provides new findings to understand the diversity of section Chaetoceros;however the inner relationships within this section remain largely unresolved.
基金financed by the Funda?ao para a Ciencia e a Tecnologia(FCT)through the project UIDP/04292/2020(https://doi.org/10.54499/UIDP/04292/2020)UIDB/04292/2020(https://doi.org/10.54499/UIDB/04292/2020)+2 种基金awarded to MARE and through project LA/P/0069/2020(https://doi.org/10.54499/LA/P/0069/2020)granted to the Associate Laboratory ARNETfunded by the European Space Agency through the SMOS Expert Support Laboratory(ESL)for SMOS Level 2 over land,ocean,ice[4000130567/20/I-BG]MCIN/AEI/10.13039/501,100,011,033 through the project INTERACT[PID2020-114623RB-C31]。
文摘The variability of the sea surface salinity measurements provided by the Soil Moisture and Ocean Salinity mission reveals the presence of a local salinity maximum(a salty tongue)in the northwestern tropical Atlantic.The sea surface salinity positive anomaly starts increasing in July,reaches its maximum in January,and then disappears.The local maximum of salinity appears in the late boreal autumn/winter,when the Amazon discharge is minimal and the salty water from the South Atlantic is transported by the North Brazil Current along the shelf break across the equator.The authors validate the satellite observations in this area and assess the vertical structure of the salinity maximum by using in situ measurements and an in situ-interpolated product.
基金funding from the European Union’s Horizon 2020 Marie Sklodowska-Curie Actions (MSCA), Innovative Training Networks (ITN), H2020-MSCA-ITN-2020 grant agreement(No.955805)。
文摘In froth flotation,overall recovery of the floatable particles consists of true recovery and recovery by entrainment,where entrainment refers to the non-selective recovery of particles in the concentrate.To understand and optimize the flotation process with regard to process conditions,it is essential to distinguish true flotation recovery from overall recovery.The established methods rely on tailored flotation experiments,unrealistic flotation conditions,or using external tracers which can be different in density and crystal structure to the mineral(s) of interest.This study presents an approach to utilize naturally occuring suitable tracers to estimate the entrainment component from overall recovery of individual particles by establishing a relationship between their settling velocity coefficient and recovery probability.Recovery probabilities of individual particles are computed using particle-based separation modelling.The approach is demonstrated for a copper ore,where naturally occurring rutile was used as the tracer to determine the entrained component of the overall recovery of chalcopyrite particles.Laboratory flotation experiments revealed that entrainment accounted for up to 6% of the overall recovery probability of fully liberated chalcopyrite particles in the fine size fractions.This approach provides a practical method for entrainment correction enabling a more accurate evaluation of true flotation recovery.
基金financial support from the Secretaría Nacional de Ciencia,Tecnologia e Innovacion(SENACYT),through the Departamento de Fortalecimiento a los Posgrados Nacionalesthe coordination of the program"MOVILIDAD DE INVESTIGACION."+3 种基金the financial support provided by PAPIIT projects IN108323 and IN111825 from DGAPA-UNAMsupport from the Agencia Nacional de Investigación y Desarrollo(ANID)through Basal project FB210003FONDECYT Regular projects 1241426 and 123044Millennium Science Initiative Program NCN2024_112。
文摘Through the analysis of representative samples of field galaxies,both local(z~0.027)and distant(z~0.7),we explore the barred galaxy fraction and its dependence on stellar mass,color,and morphology,aiming to understand the evolution of these structural components through cosmic time.To this end,two complementary bar detection techniques were employed:elliptical isophote fitting and two-dimensional Fourier analysis,both applied to deep optical images.The observational samples were drawn from previously established and calibrated catalogs to ensure a homogeneous selection in stellar mass,enabling a robust comparison between local galaxies(z~0.027)and those in the distant Universe(z~0.7).This study systematically applies both isophotal fitting and Fourier decomposition across a wide redshift range,offering a comprehensive view of the evolution of bar incidence as a function of stellar mass and morphology.The results indicate that the fraction of barred galaxies is significantly higher in the local Universe than at earlier epochs,particularly among spiral galaxies.Furthermore,a clear correlation is observed between the presence of bars and stellar mass,especially in the high-mass regime(log(M_*/M☉)>10.5).In distant galaxies,this fraction is lower across all mass ranges,which may be related to more active dynamical processes.Overall,the findings reinforce the idea that stellar bars emerge as a consequence of dynamical cooling and the progressive stabilization of galactic disks,playing a key role in gas transport and the internal structural evolution of galaxies from z~1 to the present day.
文摘Cetaceans include the largest animals ever to have lived onearth and are uniparous(producing a single calf at each birth)across the infraorder.However,instances of multiple fetuseshave been observed naturally among uniparous mammals,including cetaceans.Despite this,there is no known documented case of twins in cetaceans successfully carried to termin the wild(Perrin and Donovan 1984),and if such casesexist,they would be diffcult to detect.
文摘Sickle cell anemia (SCA) is a prevalent genetic disorder primarily affecting individuals of African descent and populations in malaria-endemic regions, with significant global public health implications. Sickle cell crises are their most common acute complication, characterized by episodes of intense pain and systemic manifestations that impair quality of life and impose a high healthcare burden. We present the case of a 19-year-old male diagnosed with SCA since the age of two, who developed a sickle cell crisis precipitated by right basal pneumonia. The patient exhibited sudden-onset, cyclic lumbar pain with progressive dyspnea. Initial management included multimodal pain control, volume optimization, and targeted antimicrobial therapy to achieve clinical stabilization. This case underscores the importance of a comprehensive approach to managing sickle cell crises, addressing both symptomatic relief and the prevention and treatment of complications. It also highlights the need for public health strategies promoting early diagnosis, access to disease-modifying therapies such as hydroxyurea, and interdisciplinary follow-up to mitigate the socioeconomic and clinical impact of SCA.
基金Supported by Comisión Sectorial de Investigación Científica(CSIC-Research Group 88180)The Agencia Nacional de Investigación e Innovación/Sistema Nacional de Investigadores(ANII/SNI)The Programa de Desarrollo de las Ciencias Básicas(PEDECIBA),Uruguay.
文摘BACKGROUND Hypoxia in oral cancer promotes tumoral invasion by inducing epithelial-mesenchymal transition,leading to aggressive tumor progression.AIM To characterize the expression of hypoxia-inducible factor 1-alpha(HIF-1α)at the invasive tumor front(ITF)in comparison to tumor islands(TI)in oral squamous cell carcinoma(OSCC)and to explore its relationship with E-cadherin and Vimentin expression.METHODS Thirty-eight cases of OSCC and five cases of normal oral mucosa(NOM)were included in this study.The ITF was identified based on the region and immune expression of AE1/AE3.Immunohistochemistry was performed to assess the expression of HIF-1α,Vimentin,and E-cadherin.The immunostaining was analyzed using an immunoreactive score,and the results were illustrated using immunofluorescence.RESULTS HIF-1αexpression was significantly higher in the TI region compared to the ITF region(P=0.0134).Additionally,a significant difference was observed between TI and NOM(P=0.0115).In the ITF regions,HIF-1αexpression showed a significant correlation with Vimentin expression,with higher levels of HIF-1αassociated with increased Vimentin expression(P=0.017).CONCLUSION Based on the results of this study,HIF-1αappears to play a distinct role in OSCC tumor progression,underscoring the importance of exploring hypoxia-driven changes in cellular phenotype at the ITF of OSCC.Further research is needed to better understand their impact on OSCC prognosis.
