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1.
Opt Lett ; 49(8): 1923-1926, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38621040

RESUMO

In this paper, we investigate a two-dimensional photonic array featuring a circular shape and an alternating gain and loss pattern. Our analysis revolves around determining the presence and resilience of optical ring modes with varying vorticity values. This investigation is conducted with respect to both the array's length and the strength of the non-Hermitian parameter. For larger values of the array's length, we observe a reduction in the stability domain as the non-Hermitian parameter increases. Interestingly, upon increasing the vorticity of the optical modes, full stability windows emerge for shorter lattice size regime.

2.
Gen Dent ; 71(2): 36-41, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36825972

RESUMO

Maxillofacial defects created by the surgical resection of a tumor negatively impact the mastication, phonation, swallowing, and psychological function of patients. A 68-year-old woman received a diagnosis of oral squamous cell carcinoma involving the hard palate. The hemimaxillectomy procedure for tumor resection created a defect on the left side of the palate. This case report describes the patient's cancer treatment from presurgical planning to final rehabilitation with a conventional obturator and subsequent follow-up care for 1 year. The rehabilitation strategy was satisfactory for the patient, reestablishing lost function and esthetics.


Assuntos
Carcinoma de Células Escamosas , Neoplasias Bucais , Feminino , Humanos , Idoso , Obturadores Palatinos , Palato Duro
3.
Int J Mol Sci ; 22(16)2021 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-34445213

RESUMO

Titanium surface is an important factor in achieving osseointegration during the early wound healing of dental implants in alveolar bone. The purpose of this study was to evaluate sandblasted-etched surface implants to investigate the osseointegration. In the present study, we used two different types of sandblasted-etched surface implants, an SLA™ surface and a Nanoblast Plus™ surface. Roughness and chemical composition were evaluated by a white light interferometer microscope and X-ray photoelectron spectroscopy, respectively. The SLA™ surface exhibited the higher values (Ra 3.05 µm) of rugosity compared to the Nanoblast Plus™ surface (Ra 1.78 µm). Both types of implants were inserted in the femoral condyles of ten New Zealand white rabbits. After 12 weeks, histological and histomorphometric analysis was performed. All the implants were osseointegrated and no signs of infection were observed. Histomorphometric analysis revealed that the bone-implant contact % (BIC) ratio was similar around the SLA™ implants (63.74 ± 13.61) than around the Nanoblast Plus™ implants (62.83 ± 9.91). Both implant surfaces demonstrated a favorable bone response, confirming the relevance of the sandblasted-etched surface on implant osseointegration.


Assuntos
Fêmur , Implantes Experimentais , Osseointegração , Titânio , Animais , Fêmur/lesões , Fêmur/metabolismo , Fêmur/patologia , Coelhos , Propriedades de Superfície
4.
Molecules ; 26(20)2021 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-34684778

RESUMO

Biohydrometallurgy recovers metals through microbially mediated processes and has been traditionally applied for the extraction of base metals from low-grade sulfidic ores. New investigations explore its potential for other types of critical resources, such as rare earth elements. In recent times, the interest in rare earth elements (REEs) is growing due to of their applications in novel technologies and green economy. The use of biohydrometallurgy for extracting resources from waste streams is also gaining attention to support innovative mining and promote a circular economy. The increase in wastes containing REEs turns them into a valuable alternative source. Most REE ores and industrial residues do not contain sulfides, and bioleaching processes use autotrophic or heterotrophic microorganisms to generate acids that dissolve the metals. This review gathers information towards the recycling of REE-bearing wastes (fluorescent lamp powder, spent cracking catalysts, e-wastes, etc.) using a more sustainable and environmentally friendly technology that reduces the impact on the environment.


Assuntos
Resíduos Industriais/análise , Metalurgia/métodos , Metais Terras Raras/isolamento & purificação , Microbiologia Industrial/métodos , Mineração , Reciclagem/métodos
5.
Muscle Nerve ; 61(3): 383-386, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31879960

RESUMO

BACKGROUND: A new technique to obtain the sensory nerve action potential (SNAP) of the medial femoral cutaneous nerve is described. METHODS: SNAPs were recorded from 104 subjects with a bar recording electrode 10 cm proximal to the patella along an imaginary line drawn between the medial edge of the patella and the femoral pulse below the inguinal ligament. Stimulation was applied 14 cm proximal to the recording point. RESULTS: There were 104 healthy subjects. Onset latency of the SNAPs was 2.20 ± 0.16 ms (mean ± SD), peak latency was 2.70 ± 0.16 ms, peak-to-peak amplitude was 7.5 ± 3.0 µV, and conduction velocity was 51.5 ± 3.0 m/s. The side-to-side difference in the mean amplitude was 22.27 ± 13.6%. CONCLUSIONS: This new technique is easy, reliable, and reproducible, and should prove useful for the evaluation of neuropathies of the medial femoral cutaneous nerve.


Assuntos
Potenciais de Ação , Eletrodiagnóstico/métodos , Nervo Femoral/fisiologia , Condução Nervosa , Adolescente , Adulto , Idoso , Eletrodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Patela , Adulto Jovem
6.
Physica A ; 557: 124876, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32834434

RESUMO

This paper investigates on the alpha-stable distribution capacity to capture the probability of market crashes by means of the dynamic forecasting of its alpha and beta parameters. On the basis of the GARCH-stable model, we design a market crash forecasting methodology that involves three-stepwise procedure: (i) Recursively estimation the GARCH-stable parameters through a rolling window; (ii) alpha-stable parameters forecasting according to a VAR model; and (iii) Crash probabilities forecasting and analysis. The model performance for alternative crash definitions is assessed in terms of different accuracy criteria, and compared with a random walk model as benchmark. Our applications to a wide variety of stock indexes for developed and emerging markets reveals a high degree of accuracy and replicability of the results. Hence the model represents an interesting tool for risk management and the design of early warning systems for future crashes.

7.
J Clin Psychol ; 76(1): 239-245, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31583717

RESUMO

OBJECTIVE: Further research is needed on parenting practices among parents of children with attention-deficit/hyperactivity disorder (ADHD), as these practices impact children's development and outcomes. This study analyzes these practices, distinguishing between parents' and children's gender. METHOD: Parental warmth (affection-communication and criticism-rejection responses) and control (inductive, strict, and indulgent discipline styles) were assessed in both parents of 81 children diagnosed with ADHD (aged 6-17 years). RESULTS: Mothers reported greater affection-communication responses and use of inductive disciplinary practices than fathers. Higher use of maternal strict practices was associated with female children, regardless of their age, subtype, medication, or comorbidities. However, parental practices used with male children were affected by children's age and subtype. CONCLUSIONS: Warmth levels and discipline styles used by parents of children with ADHD may differ depending on the gender of both parents and children. The implications of these findings for understanding gender differences associated with ADHD are discussed.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade , Relações Pais-Filho , Poder Familiar , Adolescente , Adulto , Criança , Feminino , Humanos , Masculino , Fatores Sexuais
8.
Cladistics ; 34(5): 517-541, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34706484

RESUMO

The most extensive combined phylogenetic analyses of the subclass Marchantiidae yet undertaken was conducted on the basis of morphological and molecular data. The morphological data comprised 126 characters and 56 species. Taxonomic sampling included 35 ingroup species with all genera and orders of Marchantiidae sampled, and 21 outgroup species with two genera of Blasiidae (Marchantiopsida), 15 species of Jungermanniopsida (the three subclasses represented) and the three genera of Haplomitriopsida. Takakia ceratophylla (Bryophyta) was employed to root the trees. Character sampling involved 92 gametophytic and 34 sporophytic traits, supplemented with ten continuous characters. Molecular data included 11 molecular markers: one nuclear ribosomal (26S), three mitochondrial genes (nad1, nad5, rps3) and seven chloroplast regions (atpB, psbT-psbH, rbcL, ITS, rpoC1, rps4, psbA). Searches were performed under extended implied weighting, weighting the character blocks against the average homoplasy. Clade stability was assessed across three additional weighting schemes (implied weighting corrected for missing entries, standard implied weighting and equal weighting) in three datasets (molecular, morphological and combined). The contribution from different biological phases regarding node recovery and diagnosis was evaluated. Our results agree with many of the previous studies but cast doubt on some relationships, mainly at the family and interfamily level. The combined analyses underlined the fact that, by combining data, taxonomic enhancements could be achieved regarding taxon delimitation and quality of diagnosis. Support values for many clades of previous molecular studies were improved by the addition of morphological data. The long-held assumption that morphology may render spurious or low-quality results in this taxonomic group is challenged. The morphological trends previously proposed are re-evaluated in light of the new phylogenetic scheme.

9.
Salud Publica Mex ; 59Suppl 1(Suppl 1): 30-39, 2017.
Artigo em Espanhol | MEDLINE | ID: mdl-28658450

RESUMO

OBJECTIVE:: To identify factors associated with susceptibility, tobacco use and addiction in young people from 13 to 15 years of age, to determine conditions of risk and identify possible correlates to the development of public policies on smoking in Costa Rica. MATERIALS AND METHODS:: Information available from the four rounds of the Global Youth Tobacco Survey (GYTS) Costa Rica was used. It was based on a sample size of 11 540 youngsters from public and private schools. Indicators of interest and logistic regression models for smoking, susceptibility and addiction were estimated. RESULTS:: The prevalence of current consumption shows a significant decrease over the 14 years of the study (17.3% in 1999 and 5.0% in 2013) and, to a lesser intensity, in the index of smoking susceptibility (19.3% in 1999 and 12.4% in 2013). The proportion of young people with addiction has shown a significant increase in the same period. CONCLUSIONS:: The conditions that explained the significant reduction in smoking prevalence and less susceptibility must be maintained and deepened to achieve full compliance of the MPower measures.


Assuntos
Fumar/epidemiologia , Tabagismo/epidemiologia , Adolescente , Costa Rica/epidemiologia , Suscetibilidade a Doenças/epidemiologia , Feminino , Humanos , Masculino , Fatores de Risco
10.
Sensors (Basel) ; 17(4)2017 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-28430119

RESUMO

Weather conditions can affect sensors' readings when sampling outdoors. Although sensors are usually set up covering a wide range of conditions, their operational range must be established. In recent years, depth cameras have been shown as a promising tool for plant phenotyping and other related uses. However, the use of these devices is still challenged by prevailing field conditions. Although the influence of lighting conditions on the performance of these cameras has already been established, the effect of wind is still unknown. This study establishes the associated errors when modeling some tree characteristics at different wind speeds. A system using a Kinect v2 sensor and a custom software was tested from null wind speed up to 10 m·s-1. Two tree species with contrasting architecture, poplars and plums, were used as model plants. The results showed different responses depending on tree species and wind speed. Estimations of Leaf Area (LA) and tree volume were generally more consistent at high wind speeds in plum trees. Poplars were particularly affected by wind speeds higher than 5 m·s-1. On the contrary, height measurements were more consistent for poplars than for plum trees. These results show that the use of depth cameras for tree characterization must take into consideration wind conditions in the field. In general, 5 m·s-1 (18 km·h-1) could be established as a conservative limit for good estimations.


Assuntos
Árvores , Folhas de Planta , Populus , Vento
11.
Neurourol Urodyn ; 35(7): 847-50, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-26179109

RESUMO

OBJECTIVES: To validate in Spanish (Spain) a self-administered questionnaire on the quality of life (QoL) specific to nocturia in an older adult male population. MATERIAL AND METHODS: We analysed the Spanish version of the ICIQ-Nqol questionnaire (provided by ICIQ who owns the copyright), which meets the translation criteria required by the validation protocol. The study included 69 male patients older than 60 years of age with 1 or more nocturia episodes. The participants completed the questionnaire on two occasions, along with other Spanish-validated questionnaires that measure the QoL related to urinary symptoms. We analysed the internal reliability and consistency, reproducibility, convergent validity and discriminant validity. RESULTS: The study included 69 men, with a mean age of 70.64 years (range, 60-87 years). Both the overall scale and the energy/sleep subscale met the minimum criteria for internal reliability and consistency. A good correlation has been demonstrated between the overall index of the ICIQ-Nqol questionnaire and the other questionnaires included in the study. The reproducibility (test-retest reliability) of both the overall scale and subscales of the ICIQ-Nqol and the other questionnaires was demonstrated. Conclusions The ICIQ-Nqol questionnaire has been shown to be an appropriate instrument for assessing the symptomatic intensity and impact on the QoL of patients with nocturia. This study confirms its validity for a Spanish-speaking male population. Neurourol. Urodynam. 35:847-850, 2016. © 2015 Wiley Periodicals, Inc.


Assuntos
Noctúria/diagnóstico , Qualidade de Vida , Inquéritos e Questionários , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Reprodutibilidade dos Testes , Espanha , Avaliação de Sintomas , Traduções
12.
Sensors (Basel) ; 16(8)2016 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-27517934

RESUMO

Many environmental incidents affect large areas, often in rough terrain constrained by natural obstacles, which makes intervention difficult. New technologies, such as unmanned aerial vehicles, may help address this issue due to their suitability to reach and easily cover large areas. Thus, unmanned aerial vehicles may be used to inspect the terrain and make a first assessment of the affected areas; however, nowadays they do not have the capability to act. On the other hand, ground vehicles rely on enough power to perform the intervention but exhibit more mobility constraints. This paper proposes a multi-robot sense-act system, composed of aerial and ground vehicles. This combination allows performing autonomous tasks in large outdoor areas by integrating both types of platforms in a fully automated manner. Aerial units are used to easily obtain relevant data from the environment and ground units use this information to carry out interventions more efficiently. This paper describes the platforms and sensors required by this multi-robot sense-act system as well as proposes a software system to automatically handle the workflow for any generic environmental task. The proposed system has proved to be suitable to reduce the amount of herbicide applied in agricultural treatments. Although herbicides are very polluting, they are massively deployed on complete agricultural fields to remove weeds. Nevertheless, the amount of herbicide required for treatment is radically reduced when it is accurately applied on patches by the proposed multi-robot system. Thus, the aerial units were employed to scout the crop and build an accurate weed distribution map which was subsequently used to plan the task of the ground units. The whole workflow was executed in a fully autonomous way, without human intervention except when required by Spanish law due to safety reasons.


Assuntos
Aeronaves , Monitoramento Ambiental/métodos , Robótica/métodos , Tecnologia sem Fio , Agricultura , Herbicidas , Humanos , Plantas Daninhas , Software
13.
Sensors (Basel) ; 16(3): 276, 2016 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-26927102

RESUMO

The concept of precision agriculture, which proposes farming management adapted to crop variability, has emerged in recent years. To effectively implement precision agriculture, data must be gathered from the field in an automated manner at minimal cost. In this study, a small autonomous field inspection vehicle was developed to minimise the impact of the scouting on the crop and soil compaction. The proposed approach integrates a camera with a GPS receiver to obtain a set of basic behaviours required of an autonomous mobile robot to inspect a crop field with full coverage. A path planner considered the field contour and the crop type to determine the best inspection route. An image-processing method capable of extracting the central crop row under uncontrolled lighting conditions in real time from images acquired with a reflex camera positioned on the front of the robot was developed. Two fuzzy controllers were also designed and developed to achieve vision-guided navigation. A method for detecting the end of a crop row using camera-acquired images was developed. In addition, manoeuvres necessary for the robot to change rows were established. These manoeuvres enabled the robot to autonomously cover the entire crop by following a previously established plan and without stepping on the crop row, which is an essential behaviour for covering crops such as maize without damaging them.


Assuntos
Produtos Agrícolas , Sistemas de Informação Geográfica/instrumentação , Robótica/instrumentação , Agricultura/métodos , Humanos , Processamento de Imagem Assistida por Computador/métodos , Zea mays/crescimento & desenvolvimento
14.
Sensors (Basel) ; 15(3): 5402-28, 2015 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-25751079

RESUMO

This paper describes a supervisor system for monitoring the operation of automated agricultural vehicles. The system analyses all of the information provided by the sensors and subsystems on the vehicles in real time and notifies the user when a failure or potentially dangerous situation is detected. In some situations, it is even able to execute a neutralising protocol to remedy the failure. The system is based on a distributed and multi-level architecture that divides the supervision into different subsystems, allowing for better management of the detection and repair of failures. The proposed supervision system was developed to perform well in several scenarios, such as spraying canopy treatments against insects and diseases and selective weed treatments, by either spraying herbicide or burning pests with a mechanical-thermal actuator. Results are presented for selective weed treatment by the spraying of herbicide. The system successfully supervised the task; it detected failures such as service disruptions, incorrect working speeds, incorrect implement states, and potential collisions. Moreover, the system was able to prevent collisions between vehicles by taking action to avoid intersecting trajectories. The results show that the proposed system is a highly useful tool for managing fleets of autonomous vehicles. In particular, it can be used to manage agricultural vehicles during treatment operations.

15.
Pediatr Nephrol ; 29(2): 273-81, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24077647

RESUMO

OBJECTIVE: We evaluated the association between inflammation and oxidative stress with carotid intima media thickness (cIMT) and elasticity increment module (E(inc)) in pediatric patients with chronic kidney disease (CKD). METHODS: This analytical, cross-sectional study assessed 134 children aged 6-17 years with CKD. Anthropometric measurements and biochemistry of intact parathyroid hormone (iPTH), high-sensitivity C-reactive protein (CRP), interleukin (IL)-6, IL-1ß, reduced glutathione (GSH), malondialdehyde, nitric oxide, and homocysteine were recorded. Bilateral carotid ultrasound (US) was taken. Patients were compared with controls for cIMT and E(inc) using ≥ 75 percentile (PC). RESULTS: Mean cIMT was 0.528 ± 0.089 mm; E(inc) was 0.174 ± 0.121 kPa × 10(3); cIMT negatively correlated with phosphorus (r -0.19, p =0.028) and the calcium × phosphorus (Ca × P) product (r -0.26, p =0.002), and positively with iPTH (r 0.19,p =0.024). After adjusting for potential confounders, hemodialysis (HD) (ß=0.111, p =<0.001), automated peritoneal dialysis (APD) (ß=0.064, p =0.026), and Ca x P product(ß=-0.002, p =0.015) predicted cIMT (R(2)=0.296). In patients on dialysis, HD (ß=0.068, p =0.010), low-density lipoprotein cholesterol (LDL-C) (ß=0.001, p =0.048), and GSH(ß=-0.0001, p=0.041) independently predicted cIMT (R(2)=0.204); HD, hypoalbuminemia, and high iPTH increased the risk of increased cIMT. In dialysis, E(inc) was inversely associated with GSH, and in predialysis, Ca × P correlated with/predicted E(inc) (ß=0.001, p =0.009). CONCLUSIONS: cIMT and E(inc) strongly associate with several biochemical parameters and GSH but not with other oxidative stress or inflammation markers.


Assuntos
Espessura Intima-Media Carotídea , Inflamação/complicações , Estresse Oxidativo/fisiologia , Insuficiência Renal Crônica/complicações , Adolescente , Biomarcadores/análise , Criança , Pré-Escolar , Estudos Transversais , Módulo de Elasticidade , Feminino , Humanos , Masculino
16.
Biofouling ; 30(4): 501-11, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24673176

RESUMO

The aim of this work was to investigate the production of extracellular polymeric substances (EPS) by Aeromonas hydrophila grown under anaerobic conditions. EPS composition was studied for planktonic cells, cells attached to carbon fibre supports using a soluble ferric iron source and cells grown with a solid ferric iron mineral (gossan). Conventional spectrophotometric methods, Fourier transform infrared (FTIR) and confocal laser scanning microscopy (CLSM) were used to determine the main components in the biofilm extracted from the cultures. The key EPS components were proteins, indicating their importance for electron transfer reactions. Carbohydrates were observed mostly on the mineral and contained terminal mannosyl and/or terminal glucose, fucose and N-acetylgalactosamine residues.


Assuntos
Aeromonas hydrophila/metabolismo , Polímeros/metabolismo , Biofilmes , Microscopia Confocal , Polímeros/análise , Polímeros/química , Espectroscopia de Infravermelho com Transformada de Fourier
17.
Proc Natl Acad Sci U S A ; 108(47): 18989-94, 2011 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-22084108

RESUMO

Islands have traditionally been considered as migratory and evolutionary dead ends for two main reasons: island colonizers are typically assumed to lose their dispersal power, and continental back colonization has been regarded as unlikely because of niche preemption. The hypothesis that islands might actually represent dynamic refugia and migratory stepping stones for species that are effective dispersers, and in particular, for spore-producing plants, is formally tested here, using the archipelagos of the Azores, Canary Islands, and Madeira, as a model. Population genetic analyses based on nuclear microsatellite variation indicate that dispersal ability of the moss Platyhypnidium riparioides does not decrease in the island setting. The analyses further show that, unlike island populations, mainland (southwestern Europe and North Africa) populations underwent a severe bottleneck during the last glacial maximum (LGM). Our results thus refute the traditional view of islands as the end of the colonization road and point to a different perception of North Atlantic archipelagos as major sources of biodiversity for the postglacial recolonization of Europe by spore-producing plants.


Assuntos
Biodiversidade , Bryopsida/genética , Demografia , Variação Genética , Genética Populacional , Modelos Biológicos , Ilhas Atlânticas , Bryopsida/fisiologia , Citometria de Fluxo , Camada de Gelo , Desequilíbrio de Ligação , Repetições de Microssatélites/genética , Filogeografia , Dinâmica Populacional , Portugal , Espanha
18.
Front Microbiol ; 15: 1374800, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38827148

RESUMO

Acidophiles comprise a group of microorganisms adapted to live in acidic environments. Despite acidophiles are usually associated with an autotrophic metabolism, more than 80 microorganisms capable of utilizing organic matter have been isolated from natural and man-made environments. The ability to reduce soluble and insoluble iron compounds has been described for many of these species and may be harnessed to develop new or improved mining processes when oxidative bioleaching is ineffective. Similarly, as these microorganisms grow in highly acidic media and the chances of contamination are reduced by the low pH, they may be employed to implement robust fermentation processes. By conducting an extensive literature review, this work presents an updated view of basic aspects and technological applications in biomining, bioremediation, fermentation processes aimed at biopolymers production, microbial electrochemical systems, and the potential use of extremozymes.

19.
PLoS One ; 19(2): e0297840, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38422027

RESUMO

Global biodiversity is negatively affected by anthropogenic climate change. As species distributions shift due to increasing temperatures and precipitation fluctuations, many species face the risk of extinction. In this study, we explore the expected trend for plant species distributions in Central America and southern Mexico under two alternative Representative Concentration Pathways (RCPs) portraying moderate (RCP4.5) and severe (RCP8.5) increases in greenhouse gas emissions, combined with two species dispersal assumptions (limited and unlimited), for the 2061-2080 climate forecast. Using an ensemble approach employing three techniques to generate species distribution models, we classified 1924 plant species from the region's (sub)tropical forests according to IUCN Red List categories. To infer the spatial and taxonomic distribution of species' vulnerability under each scenario, we calculated the proportion of species in a threat category (Vulnerable, Endangered, Critically Endangered) at a pixel resolution of 30 arc seconds and by family. Our results show a high proportion (58-67%) of threatened species among the four experimental scenarios, with the highest proportion under RCP8.5 and limited dispersal. Threatened species were concentrated in montane areas and avoided lowland areas where conditions are likely to be increasingly inhospitable. Annual precipitation and diurnal temperature range were the main drivers of species' relative vulnerability. Our approach identifies strategic montane areas and taxa of conservation concern that merit urgent inclusion in management plans to improve climatic resilience in the Mesoamerican biodiversity hotspot. Such information is necessary to develop policies that prioritize vulnerable elements and mitigate threats to biodiversity under climate change.


Assuntos
Biodiversidade , Mudança Climática , Animais , México , América Central , Espécies em Perigo de Extinção , Florestas
20.
Materials (Basel) ; 17(16)2024 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-39203191

RESUMO

Corrosion deterioration of materials is a major problem affecting economic, safety, and logistical issues, especially in the aeronautical sector. Detecting the correct corrosion type in metal alloys is very important to know how to mitigate the corrosion problem. Electrochemical noise (EN) is a corrosion technique used to characterize the behavior of different alloys and determine the type of corrosion in a system. The objective of this research is to characterize by EN technique different aeronautical alloys (Al, Ti, steels, and superalloys) using different analysis methods such as time domain (visual analysis, statistical), frequency domain (power spectral density (PSD)), and frequency-time domain (wavelet decomposition, Hilbert Huang analysis, and recurrence plots (RP)) related to the corrosion process. Optical microscopy (OM) is used to observe the surface of the tested samples. The alloys were exposed to 3.5 wt.% NaCl and H2SO4 solutions at room temperature. The results indicate that HHT and recurrence plots are the best options for determining the corrosion type compared with the other methods due to their ability to analyze dynamic and chaotic systems, such as corrosion. Corrosion processes such as passivation and localized corrosion can be differentiated when analyzed using HHT and RP methods when a passive system presents values of determinism between 0.5 and 0.8. Also, to differentiate the passive system from the localized system, it is necessary to see the recurrence plot due to the similarity of the determinism value. Noise impedance (Zn) is one of the best options for determining the corrosion kinetics of one system, showing that Ti CP2 and Ti-6Al-4V presented 742,824 and 939,575 Ω·cm2, while Rn presented 271,851 and 325,751 Ω·cm2, being the highest when exposed to H2SO4.

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