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Fire is a dominant force shaping patterns of plant diversity in Mediterranean-type ecosystems. In these biodiversity hotspots, including California's endangered coastal scrub, many species remain hidden belowground as seeds and bulbs, only to emerge and flower when sufficient rainfall occurs after wildfire. The unique adaptations possessed by these species enable survival during prolonged periods of unfavorable conditions, but their continued persistence could be threatened by nonnative plant invasion and environmental change. Furthermore, their fleeting presence aboveground makes evaluating these threats in situ a challenge. For example, nitrogen (N) deposition resulting from air pollution is a well-recognized threat to plant diversity worldwide but impacts on fire-following species are not well understood. We experimentally evaluated the impact of N deposition on post-fire vegetation cover and richness for three years in stands of coastal sage scrub that had recently burned in a large wildfire in southern California. We installed plots receiving four levels of N addition that corresponded to the range of N deposition rates in the region. We assessed the impact of pre-fire invasion status on vegetation dynamics by including plots in areas that had previously been invaded by nonnative grasses, as well as adjacent uninvaded areas. We found that N addition reduced native forb cover in the second year post-fire while increasing the abundance of nonnative forbs. As is typical in fire-prone ecosystems, species richness declined over the three years of the study. However, N addition hastened this process, and native forb richness was severely reduced under high N availability, especially in previously invaded shrublands. An indicator species analysis also revealed that six functionally and taxonomically diverse forb species were especially sensitive to N addition. Our results highlight a new potential mechanism for the depletion of native species through the suppression of ephemeral post-fire bloom events.
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Ecossistema , Nitrogênio , Plantas , Biodiversidade , PoaceaeRESUMO
Conservation translocations are an important conservation tool commonly employed to augment declining or reestablish extirpated populations. One goal of augmentation is to increase genetic diversity and reduce the risk of inbreeding depression (i.e., genetic rescue). However, introducing individuals from significantly diverged populations risks disrupting coadapted traits and reducing local fitness (i.e., outbreeding depression). Genetic data are increasingly more accessible for wildlife species and can provide unique insight regarding the presence and retention of introduced genetic variation from augmentation as an indicator of effectiveness and adaptive similarity as an indicator of source and recipient population suitability. We used 2 genetic data sets to evaluate augmentation of isolated populations of greater sage-grouse (Centrocercus urophasianus) in the northwestern region of the species range (Washington, USA) and to retrospectively evaluate adaptive divergence among source and recipient populations. We developed 2 statistical models for microsatellite data to evaluate augmentation outcomes. We used one model to predict genetic diversity after augmentation and compared these predictions with observations of genetic change. We used the second model to quantify the amount of observed reproduction attributed to transplants (proof of population integration). We also characterized genome-wide adaptive divergence among source and recipient populations. Observed genetic diversity (HO = 0.65) was higher in the recipient population than predicted had no augmentation occurred (HO = 0.58) but less than what was predicted by our model (HO = 0.75). The amount of shared genetic variation between the 2 geographically isolated resident populations increased, which is evidence of periodic gene flow previously assumed to be rare. Among candidate adaptive genes associated with elevated fixation index (FST) (143 genes) or local environmental variables (97 and 157 genes for each genotype-environment association method, respectively), we found clusters of genes with related functions that may influence the ability of transplants to use local resources and navigate unfamiliar environments and their reproductive potential, all possible reasons for low genetic retention from augmentation.
Influencia potencial de la divergencia adaptativa a nivel genoma sobre el resultado de la reubicación para conservación en una población aislada de urogallo mayor Resumen Las reubicaciones para conservación son una herramienta importante que se usa con frecuencia para aumentar las poblaciones en declinación o reestablecer las poblaciones erradicadas. Una de las metas de este aumento es incrementar la diversidad genética y reducir el riesgo de depresión endogámica (es decir, rescate genético). Sin embargo, la introducción de individuos de una población con divergencia significativa puede perturbar los rasgos coadaptados y reducir la aptitud local (es decir, depresión exogámica). La información genética es cada vez más accesible para las especies silvestres y puede proporcionar conocimiento único con respecto a la presencia y retención de la variación genética introducida a partir del aumento como un indicador de eficiencia y las similitudes adaptativas como un indicador de la idoneidad de la población de origen y la receptora. Usamos dos conjuntos de datos genéticos para evaluar el aumento de las poblaciones aisladas del urogallo mayor (Centrocercus urophasianus) en la región noroeste de la distribución de la especie (Washington, EUA) y para evaluar de forma retrospectiva la divergencia adaptativa entre la población de origen y la receptora. Desarrollamos dos modelos estadísticos para los datos microsatelitales para así evaluar los resultados del aumento. Usamos un modelo para predecir la diversidad genética después del aumento y comparamos estas predicciones con observaciones del cambio genético. Usamos el segundo modelo para cuantificar el aumento de la reproducción observada atribuida a las reubicaciones (evidencia de la integración poblacional). También caracterizamos la divergencia adaptativa a nivel genoma entre la población de origen y la población receptora. La diversidad genética observada (HO = 0.65) fue mayor de lo que se predijo en la población receptora de no haber ocurrido el aumento (HO = 0.58) pero menor de lo que se predijo en nuestro modelo (HO = 0.75). El aumento de la variación genética compartida entre las dos poblaciones residentes geográficamente aisladas incrementó, lo cual es evidencia de un flujo génico periódico que antes se supuso casi no ocurría. Entre los genes adaptativos candidatos asociados a una FST elevada (143 genes) o a variables ambientales locales (97 y 157 genes para cada método de asociación entre el ambiente y el genotipo, respectivamente) encontramos grupos de genes con funciones relacionadas que pueden influir sobre la habilidad de cada reubicación para usar recursos locales y navegar ambientes desconocidos y su potencial reproductivo, todas posibles razones para la baja retención genética en el aumento.
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Conservação dos Recursos Naturais , Galliformes , Variação Genética , Repetições de Microssatélites , Conservação dos Recursos Naturais/métodos , Animais , Galliformes/genética , Galliformes/fisiologia , Repetições de Microssatélites/genética , Washington , Reprodução/genéticaRESUMO
Staphylococcus aureus, particularly multi-drug resistant strains, presents significant challenges in dairy farming due to its role in causing bovine mastitis, which leads to substantial economic losses and limited treatment options. Seeking alternative therapies, we investigated the potential of a topical formulation derived from the medicinal herb Salvia officinalis to combat S. aureus growth and biofilms associated with bovine mastitis. Through systematic extraction in different solvents and fractionation by column chromatography, we isolated and identified three key multicyclic terpenoids-ferruginol, sugiol, and sclareol-exhibiting significant antimicrobial activity. The formulation effectively inhibited biofilm formation, with minimum inhibitory concentration (MIC) values ranging from 0.09 to 0.74 mg·mL-1 against clinical S. aureus strains, comparable to or lower than those of the pure compounds. Moreover, it displayed robust anti-adhesive properties, reducing biofilm formation by 20% to 79% at subinhibitory concentrations. Furthermore, the formulation successfully disrupted pre-existing biofilms, achieving reductions ranging from 30% to 82%. Cytotoxicity assays confirmed the safety of the formulation on mammary epithelial cells, with cell viability maintained at 100% at MIC. Our findings underscore the therapeutic potential of Salvia officinalis-derived compounds in managing bovine mastitis caused by S. aureus, emphasizing their antimicrobial efficacy and safety profile.
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OBJECTIVE: The purpose of this study is to investigate how cognition, as measured using the Self-Administered Gerocognitive Examination Test (SAGE), and age affect speech recognition scores in older adults (age > 65) at one year and two years after cochlear implantation. STUDY DESIGN: This is a prospective study. SETTING: This study was conducted at a single institution. METHODS: Unilateral cochlear implantation was performed by two surgeons on adult patients (>65 years) with postlingual bilateral sensorineural hearing loss. There were 230 patients who underwent cochlear implantation from January 2016 to June 2023. Fifty-five of these patients completed the SAGE questionnaire before implantation, one year after implantation, and 2 years after implantation. Paired t-test analysis was used to evaluate pre- and post-operative speech recognition scores (CNC, AzBio in Quiet). RESULTS: Patients who had normal preoperative cognition on SAGE showed greater improvement in postoperative speech recognition tests at 1 year and 2 years after implantation compared with patients who showed preoperative cognitive impairment. There were no significant differences in postoperative speech outcome between age group 1 (between 65 and 80 years old) and age group 2 (over 80 years old) cochlear implant recipients. There were no changes in cognitive SAGE scores after 2 years implantation. CONCLUSION: Cognitive function, as measured by SAGE, is a more reliable predictor than age in determining speech recognition improvement after cochlear implantation. Cochlear implantation did not improve postoperative cognition.
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Implante Coclear , Implantes Cocleares , Percepção da Fala , Humanos , Idoso , Lactente , Estudos Prospectivos , Fala , Resultado do Tratamento , CogniçãoRESUMO
Salvia lanigera Poir. is a small herbaceous perennial species with violet flowers that grows in low-altitude deserts, and sandy loam. During the collection of S. lanigera, unusual populations with white flowers were found. Therefore, the two populations (violet- and white-flowered) were subjected to comparative investigations, including DNA fingerprinting, chemical composition, and biological evaluation. The two populations showed DNA variations, with 6.66 % polymorphism in ISSR and 25 % in SCoT markers. GC/MS and UHPLC/HRMS of aqueous methanol extracts, led to the tentative identification of 43 and 50 compounds in both populations. In addition, the structures of nine compounds, including four first-time reported compounds in the species, were confirmed by NMR. Furthermore, the total extracts exhibited weak radical scavenging activity against DPPH and a lower inhibitory effect towards acetylcholinesterase. In conclusion, the obtained data suggested that the white-colored flower could be an additional important character record for the Egyptian S. lanigera.
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Impressões Digitais de DNA , Flores , Metabolômica , Salvia , Salvia/química , Salvia/metabolismo , Egito , Flores/química , Flores/metabolismo , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologia , Compostos de Bifenilo/antagonistas & inibidores , Cromatografia Gasosa-Espectrometria de Massas , Picratos/antagonistas & inibidores , Acetilcolinesterase/metabolismo , Inibidores da Colinesterase/farmacologia , Inibidores da Colinesterase/química , Inibidores da Colinesterase/isolamento & purificação , Inibidores da Colinesterase/metabolismo , Cromatografia Líquida de Alta PressãoRESUMO
As part of our interest in the volatile phytoconstituents of aromatic plants of the Great Basin, we have obtained essential oils of Ambrosia acanthicarpa (three samples), Artemisia ludoviciana (12 samples), and Gutierrezia sarothrae (six samples) from the Owyhee Mountains of southwestern Idaho. Gas chromatographic analyses (GC-MS, GC-FID, and chiral GC-MS) were carried out on each essential oil sample. The essential oils of A. acanthicarpa were dominated by monoterpene hydrocarbons, including α-pinene (36.7-45.1%), myrcene (21.6-25.5%), and ß-phellandrene (4.9-7.0%). Monoterpene hydrocarbons also dominated the essential oils of G. sarothrae, with ß-pinene (0.5-18.4%), α-phellandrene (2.2-11.8%), limonene (1.4-25.4%), and (Z)-ß-ocimene (18.8-39.4%) as major components. The essential oils of A. ludoviciana showed wide variation in composition, but the relatively abundant compounds were camphor (0.1-61.9%, average 14.1%), 1,8-cineole (0.1-50.8%, average 11.1%), (E)-nerolidol (0.0-41.0%, average 6.8%), and artemisia ketone (0.0-46.1%, average 5.1%). This is the first report on the essential oil composition of A. acanthicarpa and the first report on the enantiomeric distribution in an Ambrosia species. The essential oil compositions of A. ludoviciana and G. sarothrae showed wide variation in composition in this study and compared with previous studies, likely due to subspecies variation.
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Artemisia , Óleos Voláteis , Óleos Voláteis/química , Artemisia/química , Ambrosia , Idaho , Monoterpenos/análiseRESUMO
Essential oil (EO) of Salvia spp. has been widely used for culinary purposes and in perfumery and cosmetics, as well as having beneficial effects on human health. The present study aimed to investigate the quantitative and qualitative variations in EOs in wild-growing and cultivated pairs of samples from members in four Salvia sections or three clades, namely S. argentea L. (Sect. Aethiopis; Clade I-C), S. ringens Sm. (Sect. Eusphace; Clade I-D), S. verticillata L. (Sect. Hemisphace; Clade I-B), S. amplexicaulis Lam., and S. pratensis L. (Sect. Plethiosphace; Clade I-C). Furthermore, the natural variability in EO composition due to different genotypes adapted in different geographical and environmental conditions was examined by employing members of three Salvia sections or two phylogenetic clades, namely S. sclarea L. (six samples; Sect. Aethiopis or Clade I-C), S. ringens (three samples; Sect. Eusphace or Clade I-D), and S. amplexicaulis (five samples; Sect. Plethiosphace or Clade I-C). We also investigated the EO composition of four wild-growing species of two Salvia sections, i.e., S. aethiopis L., S. candidissima Vahl, and S. teddii of Sect. Aethiopis, as well as the cultivated material of S. virgata Jacq. (Sect. Plethiosphace), all belonging to Clade I-C. The EO composition of the Greek endemic S. teddii is presented herein only for the first time. Taken together, the findings of previous studies are summarized and critically discussed with the obtained results. Chemometric analysis (PCA, HCA, and clustered heat map) was used to identify the sample relationships based on their chemical classes, resulting in the classification of two distinct groups. These can be further explored in assistance of classical or modern taxonomic Salvia studies.
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Óleos Voláteis , Salvia , Humanos , Quimiometria , Filogenia , Genótipo , Salvia/genéticaRESUMO
This study examines the effects of various factors, including socioeconomic status, built environment, access to healthcare, educational level, social participation, and economic stability, on older adults' psychological health. The current study analyzed a nationally representative sub-sample of 2,577 respondents aged 50 and above from the World Health Organization's Study on Global AGEing and Adult Health (WHO SAGE) Wave 2. WHO SAGE Wave 2 is cross-sectional data collected via in-person structured interviews. Ordinal least square (OLS) was used to measure the average effect of social determinants of health (SDoH), and quantile regression analysis was used to determine the effects of SDoH on older adults' psychological health at different quantiles, specifically 10th, 50th, and 90th percentiles. Significant determinants of psychological health across all quantiles included age, healthcare access, marital status, economic stability, and neighborhood and built environment. However, the degrees of significance for residence, gender, educational level, chronic diseases, and social participation varied between quantiles, showing differing effects on older adults with high or low psychological health. Religion was insignificant across all quantiles. This study highlights the need for governments and public health agencies to develop targeted interventions and strategies that support the psychological well-being of older adults in the country.
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Saúde Mental , Determinantes Sociais da Saúde , Humanos , Masculino , Feminino , Idoso , Gana/epidemiologia , Pessoa de Meia-Idade , Estudos Transversais , Idoso de 80 Anos ou mais , Fatores Socioeconômicos , Participação Social/psicologiaRESUMO
I briefly describe my early life and how, through a series of serendipitous events, I became a genetic epidemiologist. I discuss how the Elston-Stewart algorithm was discovered and its contribution to segregation, linkage, and association analysis. New linkage findings and paternity testing resulted from having a genotyping lab. The different meanings of interaction-statistical and biological-are clarified. The computer package S.A.G.E. (Statistical Analysis for Genetic Epidemiology), based on extensive method development over two decades, was conceived in 1986, flourished for 20 years, and is now freely available for use and further development. Finally, I describe methods to estimate and test hypotheses about familial correlations, and point out that the liability model often used to estimate disease heritability estimates the heritability of that liability, rather than of the disease itself, and so can be highly dependent on the assumed distribution of that liability.
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Algoritmos , Ligação Genética , Modelos Genéticos , Epidemiologia Molecular , História do Século XX , História do Século XXI , HumanosRESUMO
Genetic variation is a well-known indicator of population fitness yet is not typically included in monitoring programs for sensitive species. Additionally, most programs monitor populations at one scale, which can lead to potential mismatches with ecological processes critical to species' conservation. Recently developed methods generating hierarchically nested population units (i.e., clusters of varying scales) for greater sage-grouse (Centrocercus urophasianus) have identified population trend declines across spatiotemporal scales to help managers target areas for conservation. The same clusters used as a proxy for spatial scale can alert managers to local units (i.e., neighborhood-scale) with low genetic diversity, further facilitating identification of management targets. We developed a genetic warning system utilizing previously developed hierarchical population units to identify management-relevant areas with low genetic diversity within the greater sage-grouse range. Within this warning system we characterized conservation concern thresholds based on values of genetic diversity and developed a statistical model for microsatellite data to robustly estimate these values for hierarchically nested populations. We found that 41 of 224 neighborhood-scale clusters had low genetic diversity, 23 of which were coupled with documented local population trend decline. We also found evidence of cross-scale low genetic diversity in the small and isolated Washington population, unlikely to be reversed through typical local management actions alone. The combination of low genetic diversity and a declining population suggests relatively high conservation concern. Our findings could further facilitate conservation action prioritization in combination with population trend assessments and (or) local information, and act as a base-line of genetic diversity for future comparison. Importantly, the approach we used is broadly applicable across taxa.
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Animais Selvagens , Galliformes , Animais , Conservação dos Recursos Naturais/métodos , Ecossistema , Modelos EstatísticosRESUMO
OBJECTIVE: The objective of this study was to review the characteristics, efficacy, and safety of zuranolone in the management of postpartum depression (PPD). DATA SOURCES: Literature was identified using PubMed (1966-August 2023) and EMBASE (1973-August 2023) and clinicaltrials.gov. Search terms included zuranolone, SAGE-217, and PPD with further limitation of those published in English. STUDY SELECTION AND DATA EXTRACTION: Articles selected for inclusion included trials evaluating zuranolone for the treatment of PPD. DATA SYNTHESIS: Zuranolone was evaluated for the treatment of moderate to severe PPD in 2 phase III trials. Both studies resulted in statistically significant improvement in depressive symptoms at day 15 (P = 0.003 and P < 0.001). Sustained differences in remission rates favoring zuranolone were found in both studies at day 45 compared with placebo (P = 0.01 and P < 0.05). Zuranolone was well tolerated, with somnolence, dizziness, headache, and sedation reported as the most common side effects. RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE IN COMPARISON TO EXISTING DRUGS: Zuranolone is only the second medication approved by the Food and Drug Administration (FDA) for PPD and offers an advantage over brexanolone in that it can administered orally in the outpatient setting. The rapid onset of effect of zuranolone is advantageous to traditional antidepressant therapy which can be weeks to months; however, limited information is available on safety during lactation. CONCLUSIONS: The recent FDA approval of oral zuranolone for PPD offers a second rapid-acting treatment for PPD, extending the opportunity for treatment to patients in the outpatient setting.
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BACKGROUND AND AIMS: Intensive glycemic control minimizes the risk of micro- and macrovascular complications in patients with type 1 diabetes (T1D). We report glycemic control in Italian participants (age groups: 26-44, 45-64, and ≥65 years) of the global SAGE study. METHODS AND RESULTS: The primary endpoint was proportion of participants who achieved an HbA1c <7% in predefined age groups. In the 523 patients with T1D, mean age was 44.6 years and mean body mass index (BMI) was 25 kg/m2. Mean HbA1c was 7.5% and 29.4% had HbA1c <7.0%, with the highest percentage in those 26-45 years (31.7%) and the lowest in those ≥65 years (20%). Altogether, 22.9% of patients achieved their physician-established individualized HbA1c target. Most patients had ≥1 symptomatic hypoglycemic episode in the previous 3 months (≤70 mg/dL 82.5%; ≤54 mg/dL 61%). Severe hypo- and hyperglycemia were experienced by 16.3% and 12% of patients, of which 7.1 and 9.5%, respectively, required hospitalization/emergency visits. More patients achieved HbA1c <7% with CSII (30%) than with multiple daily insulin injections (27.9%). In multivariate analysis, BMI (OR 0.94, 95% CI 0.89-0.99, p = 0.032) and adherence to diet (OR 0.36, 95% CI 0.18-0.70, p = 0.0028) were significantly associated with HbA1c <7.0%. CONCLUSIONS: Glycemic control can be considered good in the Italian SAGE cohort, especially in younger patients, who more frequently use pumps/continuous glucose monitoring. Greater patient education and use of technology may further support this achievement. Patients should be encouraged to maintain a low BMI and adhere to their diet.
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Diabetes Mellitus Tipo 1 , Adulto , Humanos , Glicemia , Automonitorização da Glicemia , Diabetes Mellitus Tipo 1/diagnóstico , Diabetes Mellitus Tipo 1/tratamento farmacológico , Diabetes Mellitus Tipo 1/epidemiologia , Hemoglobinas Glicadas , Controle Glicêmico/efeitos adversos , Hipoglicemiantes/efeitos adversos , Insulina/efeitos adversos , Itália/epidemiologia , Pessoa de Meia-Idade , IdosoRESUMO
BACKGROUND: The SARS-CoV-2/COVID-19 pandemic has inflicted medical and socioeconomic havoc, and despite the current availability of vaccines and broad implementation of vaccination programs, more easily accessible and cost-effective acute treatment options preventing morbidity and mortality are urgently needed. Herbal teas have historically and recurrently been applied as self-medication for prophylaxis, therapy, and symptom alleviation in diverse diseases, including those caused by respiratory viruses, and have provided sources of natural products as basis for the development of therapeutic agents. To identify affordable, ubiquitously available, and effective treatments, we tested herbs consumed worldwide as herbal teas regarding their antiviral activity against SARS-CoV-2. RESULTS: Aqueous infusions prepared by boiling leaves of the Lamiaceae perilla and sage elicit potent and sustained antiviral activity against SARS-CoV-2 when applied after infection as well as prior to infection of cells. The herbal infusions exerted in vitro antiviral effects comparable to interferon-ß and remdesivir but outperformed convalescent sera and interferon-α2 upon short-term treatment early after infection. Based on protein fractionation analyses, we identified caffeic acid, perilla aldehyde, and perillyl alcohol as antiviral compounds. Global mass spectrometry (MS) analyses performed comparatively in two different cell culture infection models revealed changes of the proteome upon treatment with herbal infusions and provided insights into the mode of action. As inferred by the MS data, induction of heme oxygenase 1 (HMOX-1) was confirmed as effector mechanism by the antiviral activity of the HMOX-1-inducing compounds sulforaphane and fraxetin. CONCLUSIONS: In conclusion, herbal teas based on perilla and sage exhibit antiviral activity against SARS-CoV-2 including variants of concern such as Alpha, Beta, Delta, and Omicron, and we identified HMOX-1 as potential therapeutic target. Given that perilla and sage have been suggested as treatment options for various diseases, our dataset may constitute a valuable resource also for future research beyond virology.
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Tratamento Farmacológico da COVID-19 , Chás de Ervas , Humanos , SARS-CoV-2 , Antivirais/farmacologia , Antivirais/uso terapêutico , Pandemias , Soroterapia para COVID-19RESUMO
Excess copper (Cu) causes the toxic effects in plants and health hazards to humans. Therefore, in this study, the effect of sodium silicate (1 mM Si) and sodium nitroprusside (200 µM SNP as a releasing NO), was assessed on Cu tolerance in Salvia officinalis L. plants exposed to 400 µM CuSO4. Results revealed that the combined supplementation with Si and SNP rather than the single application of these chemicals lowered Cu concentrations and translocation factor and increased Mg, Zn, and Fe concentrations in roots and shoots. Furthermore, combined treatment more efficiently decreased electrolyte leakage enhanced the activities of POD and APX in the leaves and roots, and improved relative water content and the content of Chl. a and Chl. b in leaves and consequently further increased tolerance index. Silicon supply enhanced NO content and applying Si + SNP more than the treatment of Si alone increased Si concentrations in the roots and shoots under Cu stress. Therefore, the reciprocal interaction of Si and NO might enhance Cu tolerance in plants, and the combined application of Si and SNP might be a promising strategy to decrease heavy metal accumulation in medicinal plants grown in polluted lands.
In most studies, co-precipitation of silicon and heavy metals in medium has been suggested as a reason for reducing heavy metal uptake in plants. In this study, the impact of Si on NO generation and the role of NO signaling in regulating Cu uptake and translocation and defensive responses were assessed to clarify another mechanism of Si in inducing Cu tolerance in sage. Furthermore, the combined application of Si and SNP has been indicated as an innovative strategy to enhance Cu tolerance and decrease heavy metal accumulation in medicinal plants grown in polluted lands.
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Cobre , Salvia officinalis , Humanos , Cobre/toxicidade , Óxido Nítrico/farmacologia , Silício/farmacologia , Biodegradação Ambiental , Antioxidantes/farmacologia , Raízes de PlantasRESUMO
In this paper, we propose a combined filtering method rooted in the application of the Sage-Husa Adaptive Kalman filtering, designed specifically to process wave sensor data. This methodology aims to boost the measurement precision and real-time performance of wave parameters. (1) This study delineates the basic principles of the Kalman filter. (2) We discuss in detail the methodology for analyzing wave parameters from the collected wave acceleration data, and deeply study the key issues that may arise during this process. (3) To evaluate the efficacy of the Kalman filter, we have designed a simulation comparison encompassing various filtering algorithms. The results show that the Sage-Husa Adaptive Kalman Composite filter demonstrates superior performance in processing wave sensor data. (4) Additionally, in Chapter 5, we designed a turntable experiment capable of simulating the sinusoidal motion of waves and carried out a detailed errors analysis associated with the Kalman filter, to facilitate a deep understanding of potential problems that may be encountered in practical application, and their solutions. (5) Finally, the results reveal that the Sage-Husa Adaptive Kalman Composite filter improved the accuracy of effective wave height by 48.72% and the precision of effective wave period by 23.33% compared to traditional bandpass filter results.
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The features of measurement and process noise are directly related to the optimal performance of the cubature Kalman filter. The maneuvering target model's high level of uncertainty and non-Gaussian mean noise are typical issues that the radar tracking system must deal with, making it impossible to obtain the appropriate estimation. How to strike a compromise between high robustness and estimation accuracy while designing filters has always been challenging. The H-infinity filter is a widely used robust algorithm. Based on the H-infinity cubature Kalman filter (HCKF), a novel adaptive robust cubature Kalman filter (ARCKF) is suggested in this paper. There are two adaptable components in the algorithm. First, an adaptive fading factor addresses the model uncertainty issue brought on by the target's maneuvering turn. Second, an improved Sage-Husa estimation based on the Mahalanobis distance (MD) is suggested to estimate the measurement noise covariance matrix adaptively. The new approach significantly increases the robustness and estimation precision of the HCKF. According to the simulation results, the suggested algorithm is more effective than the conventional HCKF at handling system model errors and abnormal observations.
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Accurate knowledge of the rotor position is essential for the control of brushless DC motors (BLDCM). Any deviation in this identification can cause fluctuations in motor current and torque, increase noise, and lead to reduced motor efficiency. This paper focused on a BLDCM equipped with a three-phase binary Hall sensor. Based on the principle of minimum deviation, this paper estimated the relative installation offset between the Hall sensors. It also provided a clear method for ideal phase commutation position recognition and eliminated the Hall sensor installation position deviation. The proposed pre-calibration method identified and eliminated the offset of the permanent magnet poles, the delay time caused by the Hall signal conditioning circuit, and the offset of the sensor signal identification due to armature response under different loads. Based on the pre-calibration results, a correction strategy for correcting the rotor position information of BLDCMs was proposed. This paper presented a self-adaptive position information prediction algorithm based on the Sage-Husa method. This filters out rotor position information deviations that are not eliminated in pre-calibration. Experimental results on a hydrogen circulation pump motor showed that, after the pre-calibration method was adopted, the Mean Square Error (MSE) of motor speed fluctuations decreased by 92.0%, motor vibration was significantly reduced, average phase current decreased by 62.8%, and the efficiency of the hydrogen circulation pump system was significantly improved. Compared to the traditional KF prediction algorithm, the Sage-Husa adaptive position information prediction algorithm reduced the speed fluctuation during the uniform speed operation stage and speed adjustment stage, the speed curve overshoot, and the commutation time deviation throughout the process by 44.8%, 56.0%, 54.9%, and 14.7%, respectively. This indicates a higher disturbance rejection ability and a more accurate and stable prediction of the commutation moment.
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The bioactivity of the versatile biodegradable biopolymer poly(lactic acid) (PLA) can be obtained by combining it with natural or synthetic compounds. This paper deals with the preparation of bioactive formulations involving the melt processing of PLA loaded with a medicinal plant (sage) and an edible oil (coconut oil), together with an organomodifed montmorillonite nanoclay, and an assessment of the resulting structural, surface, morphological, mechanical, and biological properties of the biocomposites. By modulating the components, the prepared biocomposites show flexibility, both antioxidant and antimicrobial activity, as well as a high degree of cytocompatibility, being capable to induce the cell adherence and proliferation on their surface. Overall, the obtained results suggest that the developed PLA-based biocomposites could potentially be used as bioactive materials in medical applications.
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Ácido Láctico , Polímeros , Polímeros/química , Óleo de Coco , Ácido Láctico/química , Poliésteres/químicaRESUMO
Sagebrush ecosystems of the western U.S. support ranching livelihoods and imperiled populations of the Greater Sage-grouse (Centrocercus urophasianus). Incentive-based conservation such as cost-sharing is the primary tool used by the federal government to support conservation practices on rangelands in the U.S. Financial support for adopting specific prescribed grazing practices on private land has been supported through the U.S. Department of Agriculture Natural Resources Conservation Service (NRCS)-led Sage-Grouse Initiative (SGI), initiated in 2010 as an unparalleled private and public effort to conserve Greater Sage-grouse habitat. The purpose of this research was to provide an economic assessment of the impact of this conservation program on participating ranches. Representative ranch enterprise budgets and ranch economic models were created for this analysis for eleven NRCS Major Land Resource Areas where critical sage-grouse habitat exist, including parts of Idaho, Montana, Nevada, Oregon, Washington, and Wyoming. Results of the economic assessment showed that SGI/NRCS financial support alleviated the financial impact of conservation practice adoption, but negative financial impacts were estimated in some locations and more frequently for smaller ranches. Larger ranches were found to do better under these programs on average. Results demonstrate the important role of research and government financial support in removing financial barriers to conservation adoption on rangelands.
Assuntos
Artemisia , Galliformes , Animais , Conservação dos Recursos Naturais/métodos , Ecossistema , WyomingRESUMO
Escalated wildfire activity within the western U.S. has widespread societal impacts and long-term consequences for the imperiled sagebrush (Artemisia spp.) biome. Shifts from historical fire regimes and the interplay between frequent disturbance and invasive annual grasses may initiate permanent state transitions as wildfire frequency outpaces sagebrush communities' innate capacity to recover. Therefore, wildfire management is at the core of conservation plans for sagebrush ecosystems, especially critical habitat for species of conservation concern such as the greater sage-grouse (Centrocercus urophasianus; hereafter sage-grouse). Fuel breaks help facilitate wildfire suppression by modifying behavior through fuels modification and allowing safe access points for containment by firefighters. The Bureau of Land Management has proposed to roughly double the existing fuel break network in the western U.S., centered on the Great Basin. To our knowledge, no broad-scale examination of fuel break effectiveness or the environmental conditions under which fuel breaks are expected to be most effective has been conducted. We performed a retrospective assessment of probability of fuel break contributing to wildfire containment on recorded wildfire and fuel break interactions from 1985 to 2018 within the western U.S. We characterized environmental, fuels, and weather conditions within 500 m of wildfire contact, and within 5 km of the approaching wildfire. We used a binomial mixed model within a Bayesian framework to identify relationships between these variables and fuel break success. Fuel breaks were least successful in areas classified as having low resilience to disturbance and low resistance to invasion, in areas composed of primarily woody fuels, and when operating in high temperature and low precipitation conditions. Fuel breaks were most effective in areas where fine fuels dominated and in areas that were readily accessible. Maintenance history and fuel break type also contributed to the probability of containment. Overall results indicate a complex and sometimes paradoxical relationship between landscape characteristics that promote wildfire spread and those that impact fuel break effectiveness. Finally, we developed predictive maps of fuel break effectiveness by fuel break type to further elucidate these complex relationships and to inform urgently needed fuel break placement and maintenance priorities across the sagebrush biome.