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Organic carbon derived from terrestrial plants contributes to aquatic consumers, e.g., zooplankton in lakes. The degree of the contribution depends on the availability of terrestrial organic carbon in lake organic pool and the transfer efficiency of the carbon. Terrestrial organic carbon is poor-quality food for zooplankton with a mismatch of nutrition content and was incorporated to zooplankton with much lower efficiency than phytoplankton. Contributions of terrestrial carbon to zooplankton generally decrease with an increase in phytoplankton production, indicating a preferential incorporation of phytoplankton in previous investigations. However, in eutrophic lakes, the dominating cyanobacteria were of poor quality and incorporated to consumers inefficiently too. In that case, zooplankton in eutrophic wetlands, where cyanobacteria dominate the phytoplankton production and massive terrestrial plants are inundated, may not preferentially incorporate poor food-quality phytoplankton resource to their biomass. Therefore, we hypothesize that carbon contributions of terrestrial vegetation to zooplankton and to lake particulate organic pool should be similar in such aquatic ecosystems. We tested this hypothesis by sampling zooplankton and carbon sources in Ming Lake (Jinan University Campus, southern China) which was overgrown by terrestrial plants after drying and re-flooded. After 60 days of observations at weekly (or biweekly) intervals, applying stable carbon (13C), nitrogen (15 N), and hydrogen (2H) isotopic analysis and a stable isotope mixing model, we estimated the occurrence of extensive carbon contribution (≥ 50%) of flooded terrestrial plants to cladocerans and copepods. Contribution of inundated terrestrial plants to cladocerans was similar to that to lake particulate organic pool. Thus, our study quantified the role of terrestrial carbon in eutrophic wetlands, enhancing our understanding of cross-ecosystem interactions in food webs with an emphasis on the resource quality.
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Cianobactérias , Zooplâncton , Humanos , Animais , Carbono/metabolismo , Lagos , Ecossistema , Biomassa , Cadeia Alimentar , Fitoplâncton/metabolismo , Cianobactérias/metabolismoRESUMO
The effect of proton transfer on water oxidation has hardly been measurably established in heterogeneous electrocatalysts. Herein, two isomorphous manganese phosphates (NH4 MnPO4 â H2 O and KMnPO4 â H2 O) were designed to form an ideal platform to study the effect of proton transfer on water oxidation. The hydrogen-bonding network in NH4 MnPO4 â H2 O has been proven to be solely responsible for its better activity. The differences of the proton transfer kinetics in the two materials indicate a fast proton hopping transfer process with a low activation energy in NH4 MnPO4 â H2 O. In addition, the hydrogen-bonding network can effectively promote the proton transfer between adjacent Mn sites and further stabilize the MnIII -OH intermediates. The faster proton transfer results in a higher proportion of zeroth-order in [H+ ] for OER. Thus, proton transfer-affected electrocatalytic water oxidation has been measurably observed to bring detailed insights into the mechanism of water oxidation.
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This paper reviews the development of all-solid-state ion-selective electrodes (ASSISEs) for agricultural crop detection. Both nutrient ions and heavy metal ions inside and outside the plant have a significant influence on crop growth. This review begins with the detection principle of ASSISEs. The second section introduces the key characteristics of ASSISE and demonstrates its feasibility in crop detection based on previous research. The third section considers the development of ASSISEs in the detection of corps internally and externally (e.g., crop nutrition, heavy metal pollution, soil salinization, N enrichment, and sensor miniaturization, etc.) and discusses the interference of the test environment. The suggestions and conclusions discussed in this paper may provide the foundation for additional research into ion detection for crops.
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Eletrodos Seletivos de Íons , Metais Pesados , Produtos Agrícolas , Eletrodos , Íons , Metais Pesados/análise , SoloRESUMO
Proton transfer is vital for many biological and chemical reactions. Hydrogen-bonded water-containing networks are often found in enzymes to assist proton transfer, but similar strategy has been rarely presented by synthetic catalysts. We herein report the Co corrole 1 with an appended crown ether unit and its boosted activity for the hydrogen evolution reaction (HER). Crystallographic and 1 Hâ NMR studies proved that the crown ether of 1 can grab water via hydrogen bonds. By using protic acids as proton sources, the HER activity of 1 was largely boosted with added water, while the activity of crown-ether-free analogues showed very small enhancement. Inhibition studies by adding 1)â external 18-crown-6-ether to extract water molecules and 2)â potassium ion or N-benzyl-n-butylamine to block the crown ether of 1 further confirmed its critical role in assisting proton transfer via grabbed water molecules. This work presents a synthetic example to boost HER through water-containing networks.
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In enzymes, the active site residues function differently to promote chemical reactions. Such a role-specialized division of labor has been rarely realized by synthetic catalysts. We report herein on catalytic CO2 reduction with Fe porphyrins decorated with two cationic N,N,N-trimethylbenzylamine groups in cis- or trans-arrangement. The cis-isomer outperforms the trans-isomer and reaches a TOFmax of 4.4×105 â s-1 in acetonitrile using phenol proton source. Theoretical studies revealed that the two cationic units in the cis-isomer are more effective than a single cationic unit to improve the CO2 binding, and more importantly, they function differently but cooperatively to promote the C-O bond cleavage: one interacts with the CO2 -adduct, while the other one interacts with the phenol molecule through electrostatic interactions. This work therefore presents a significant example of synthetic catalysts, which boost chemical reactions using a role-specialized strategy for substrate activation.
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Porfirinas , Dióxido de Carbono/química , Catálise , Ferro/química , Fenóis , Porfirinas/químicaRESUMO
Water nucleophilic attack (WNA) on high-valent terminal Mn-oxo species is proposed for O-O bond formation in natural and artificial water oxidation. Herein, we report an electrocatalytic water oxidation reaction with MnIII tris(pentafluorophenyl)corrole (1) in propylene carbonate (PC). O2 was generated at the MnV/IV potential with hydroxide, but a more anodic potential was required to evolve O2 with only water. With a synthetic MnV(O) complex of 1, a second-order rate constant, k2(OH-), of 7.4 × 103 M-1 s-1 was determined in the reaction of the MnV(O) complex of 1 with hydroxide, whereas its reaction with water occurred much more slowly with a k2(H2O) value of 4.4 × 10-3 M-1 s-1. This large reactivity difference of MnV(O) with hydroxide and water is consistent with different electrocatalytic behaviors of 1 with these two substrates. Significantly, during the electrolysis of 1 with water, a MnIV-peroxo species was identified with various spectroscopic methods, including UV-vis, electron paramagnetic resonance, and infrared spectroscopy. Isotope-labeling experiments confirmed that both O atoms of this peroxo species are derived from water, suggesting the involvement of the WNA mechanism in water oxidation by a Mn complex. Density functional theory calculations suggested that the nucleophilic attack of hydroxide on MnV(O) and also WNA to 1e--oxidized MnV(O) are feasibly involved in the catalytic cycles but that direct WNA to MnV(O) is not likely to be the main O-O bond formation pathway in the electrocatalytic water oxidation by 1.
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Achieving a selective 2 e- or 4 e- oxygen reduction reaction (ORR) is critical but challenging. Herein, we report controlling ORR selectivity of Co porphyrins by tuning only steric effects. We designed Co porphyrin 1 with meso-phenyls each bearing a bulky ortho-amido group. Due to the resulted steric hinderance, 1 has four atropisomers with similar electronic structures but dissimilar steric effects. Isomers αßαß and αααα catalyze ORR with n=2.10 and 3.75 (n is the electron number transferred per O2 ), respectively, but ααßß and αααß show poor selectivity with n=2.89-3.10. Isomer αßαß catalyzes 2 e- ORR by preventing a bimolecular O2 activation path, while αααα improves 4 e- ORR selectivity by improving O2 binding at its pocket, a feature confirmed by spectroscopy methods, including O K-edge near-edge X-ray absorption fine structure. This work represents an unparalleled example to improve 2 e- and 4 e- ORR by tuning only steric effects without changing molecular and electronic structures.
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Introduction: Extant studies have demonstrated the relationship between naturalness and healthiness, and the effectiveness of various food labels in influencing consumers' perception of food and subsequent food choices. However, little attention has been given to food producer labels. Methods: Drawing on Stimulation-Organism-Response theory, the current study explored the causal relationship between food producer labels and consumers' food choices. Three studies (562 participants) were employed to test the main effect, the mediating effect, and the moderating effect. Results: The results showed that: (1) food producer label could influence consumers' food choice, that is, produced-by-farmer label (vs. produced-by-enterprise label vs. control group) could significantly increase consumers' food choices, while there is no significant difference between produced-by-enterprise label and control group. (2) Perceived naturalness and standardization perception mediate the effects on consumers' food choices of food producer labels. (3) Food processing level moderates the effect of food producer label on consumers' food choices. Discussion: The current study enriches the research of food label and food choice, expands the application of Stimulation-Organism-Response theory in consumer behavior, and provides some practical suggestions for consumers, enterprise and policy-maker. Various kinds of experiments (online and offline) enhanced the conclusions' ecological validity. Finally, the limitations and future research are discussed.
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Fazendeiros , Preferências Alimentares , Humanos , Rotulagem de Alimentos/métodos , Nível de SaúdeRESUMO
Introduction: Considering the theory of self-escape, this research systematically investigates the effect of stress on consumers' preference for experiences vs. material possessions. Methods: We conducted one survey and two experiments to demonstrate the effect of stress on individuals' relative preference for experiential vs. material consumption and its psychological mechanism. Results: The findings of the three studies revealed that stress increases consumers' preference for experiences over material possessions. Additionally, self-escape motivation plays a mediating role between stress and preference for experiential consumption (vs. material consumption). Stress as a self-threat triggers individuals' motivation to escape from negative self-concept, and experiences can help individuals temporarily escape from negative self-recognition and provide more leisure value than material possessions. Therefore, individuals increase their consumption preference for experiences. Furthermore, we observed that the type of experiences plays a moderating role between stress and preference for experiential consumption (vs. material consumption). Specifically, compared with low cognitive resource demanding experiences, the effect of stress on experiential consumption disappears when experiences have a high demand for cognitive resources. Discussion: These findings extend the research on stress, experiential consumption and material consumption and provide significant advice for public mental health.
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Comportamento do Consumidor , Saúde Mental , Humanos , Motivação , Inquéritos e QuestionáriosRESUMO
With the advancement of global urbanization, ecosystem conservation and sustainable land development have become major issues. In this context, the uncoordinated and imbalanced development of the land-centered human-environment system requires urgent attention, especially in rust belt cities that pose critical challenges to regional land system sustainability. Therefore, taking Changchun City from 1990 to 2020 as an example, we identified and evaluated the ecosystem service (ES) balance and land use conflict from the perspectives of internal support and external development pressure. Based on the land system adaptation and conflict results, a coupling coordination degree model (CCDM) was constructed to investigate the spatio-temporal characteristics of land system development. The results indicated that there was an obvious downward trend in the regional ES balance, while areas with higher ES balance were mainly distributed in the eastern ecologically sound areas, and southern built-up areas presented deficient ES balance levels (i.e., demand exceeding supply), with a significant expansion trend from 1990 to 2020. Land use conflict was especially prominent in areas experiencing rapid rural-urban transformation, and the hot spots expanded noticeably. The spatio-temporal differences in the coupling coordination degree of ES balance and land use conflict were significant, whereas the land system of the study area has always been dominated by a balanced development pattern throughout the research period, except for the urban center, which tended to be in a stage of uncoordinated development, with the ES balance blocked. These findings suggest that it is necessary to coordinate urban and adjacent regions through regionally integrated efforts to alleviate the ES imbalance. This research can provide a scientific reference for analyzing regional land system states, coordinating the sustainable spatial development of ecosystems, and implementing revitalization strategies to achieve win-win land system goals.
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Conservação dos Recursos Naturais , Ecossistema , Humanos , Cidades , Urbanização , Aclimatação , ChinaRESUMO
In public health emergencies, people are more willing to save money rather than spending it, which is not conductive to economic development and recovery. Due to the absence of relevant research, the internal logic of this phenomenon is not clear. In the context of the COVID-19 pandemic, this study systematically explored whether and why public health emergencies stimulate consumers' preference for saving (vs. spending). We conducted two online surveys and used methods including stepwise regression analysis and bootstrapping to test the hypotheses. The first survey, with 1,511 participants from China in February 2020, indicates that the severity of emergencies has a significant positive impact on the populations' willingness to save (vs. spend). Risk perception plays a mediating role between the severity of emergencies and consumers' saving (vs. spending) willingness. Materialism plays a moderating role between risk perception and an individual's saving (vs. spending) willingness, individuals who are more materialistic have a lower saving (vs. spending) willingness when they perceive the risks of the pandemic. To verify the duration of the above effects, we conducted a follow-up survey consisted of 466 instances in August 2020. It is noteworthy that the above effects are not significant during the post-pandemic period. Thus, spending behavior in public health emergencies can be motived by reducing risk perception and increasing materialism. These findings can provide a valuable inspiration for public health, crisis management, and economic recovery during public health emergencies.
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This study explored how perceived control affects consumers' willingness to purchase self-improvement products (WSP) under self-deficit situations. For this purpose, three experiments were conducted to examine the following sources of control: the controllability of self-deficits (Experiment 1); the locus of control (Experiment 2); and situational perceived control (Experiment 3). According to the results, higher perceived control can reduce consumers' defensive reaction tendencies, thus increasing their willingness to purchase products that claim to improve their current deficits. Moreover, the aforementioned effect only occurs in within-domain improvement products, rather than without-domain improvement products.
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Angular and rounded shapes are two important visual elements widely used in the design of product shapes and brand logos. By introducing the power state, a psychological variable that is inherently relevant to consumers' product choices, brand preferences, and decision-making, we propose that consumers' power state influences their shape preference. Specifically, compared to low-power consumers, high-power consumers respond more positively to angular as opposed to rounded shapes, because the angular shape facilitates the expression of competence (as opposed to warmth). Through four studies, we provide consistent support for our main predictions as well as the underlying processes. Studies 1 and 2 demonstrate that consumers experiencing higher power are more likely to prefer an angular shape over a rounded shape than those experiencing lower power through different research methods, research objects, and experimental materials. On this basis, studies 3 and 4 further explore the mechanisms underlying the observed effects. These findings contribute to sensory marketing and power research and provide important implications for visual design and advertisement development.
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How to overcome informational conformity consumer behavior when faced with threats of death is a social problem in response to COVID-19. This research is based on the terror management theory, the need to belong theory and the materialism theory. It uses a theoretical model to determine the relationships between threats of death and informational conformity consumer behavior. From 1453 samples collected during outbreak of COVID-19 in China, we used a structural equation model to test multiple research hypotheses. The result shows that threats of death are positively associated with a need to belong, materialism and informational conformity consumer behavior. The need to belong and materialism can play a mediating role between threats of death and information conformity consumption behavior, and perceived social support can play a moderating role between threats of death and information conformity consumption behavior.
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Comércio , Comportamento do Consumidor , Infecções por Coronavirus , Comportamento de Busca de Informação , Pneumonia Viral , Conformidade Social , Apoio Social , Adulto , Atitude Frente a Morte , Betacoronavirus , COVID-19 , China/epidemiologia , Comportamento do Consumidor/economia , Comportamento do Consumidor/estatística & dados numéricos , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/psicologia , Morte , Feminino , Humanos , Controle Interno-Externo , Masculino , Modelos Teóricos , Pandemias , Pneumonia Viral/epidemiologia , Pneumonia Viral/psicologia , SARS-CoV-2 , Inquéritos e QuestionáriosRESUMO
Objectives: During public health emergencies, people often scramble to buy scarce goods, which may lead to panic behavior and cause serious negative impacts on public health management. Due to the absence of relevant research, the internal logic of this phenomenon is not clear. This study explored whether and why public health emergencies such as the COVID-19 pandemic stimulate consumers' preference for scarce products. Methods: Applying the questionnaire survey method, two online surveys were conducted on the Credamo data platform in China. The first survey was launched in February and collected psychological and behavioral data from 1,548 participants. Considering the likelihood of population relocation due to the pandemic, a follow-up survey was conducted in August with 463 participants who had participated in the first survey and had not relocated to other cities between February and August. The hypotheses were tested with these data through stepwise regression analysis, bootstrapping, and robustness testing. Results: Pandemic severity was found to positively affect scarce consumption behavior and the effect was found to be situational; this indicates that the impact of the pandemic on scarce consumption was only significant during the pandemic. Further, it was found that materialism plays a mediating role in the relationship between pandemic severity and scarce consumption. Finally, the need to belong was found to play a moderating role between pandemic severity and materialism. Conclusion: This study findings imply that the scarce consumption behavior during public health emergencies can be reduced by decreasing materialism and increasing the need to belong. These findings may aid government leaders in managing public health emergencies.
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COVID-19/economia , COVID-19/psicologia , Comportamento do Consumidor/estatística & dados numéricos , Emergências/economia , Emergências/psicologia , Pandemias/estatística & dados numéricos , Adulto , Idoso , Idoso de 80 Anos ou mais , China , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Saúde Pública/estatística & dados numéricos , Inquéritos e QuestionáriosRESUMO
A graphene oxide-molybdenum disulfide (GO-MoS2) composite was synthesized and utilized as the highly efficient stationary phase of open-tubular capillary electrochromatography (OT-CEC). The characterization results indicated that GO-MoS2 composite was successfully synthesized. The GO-MoS2-coated capillary column was prepared by covalent immobilization method for the determination of seven sulfonamides. The baseline separation of seven sulfonamides was achieved by GO-MoS2-coated capillary column. The linear range was 0.05-100 µg/mL for sulfisomidine, sulfathiazole, sulfamerazine, phthalylsulfathiazole and sulfacetamide, 0.1-100 µg/mL for sulfamonomethoxine and sulfachloropyridazine with a satisfactory correlation coefficients (R2) > 0.9994. This developed OT-CEC method was successfully applied to determinate of seven sulfonamides in environmental water and milk samples with good recoveries of 85.77% - 109.10% and 80.03% - 109.97%, respectively. These results indicated that GO-MoS2-coated capillary column possessed good stability and repeatability.
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Eletrocromatografia Capilar/métodos , Dissulfetos , Grafite , Molibdênio , Sulfonamidas/análise , Sulfonamidas/isolamento & purificaçãoRESUMO
Lily basal rot, caused by Fusarium oxysporum f. sp. lilii, is one of the most serious diseases of lily. Although the lily germplasm which is resistant to F. oxysporum has been used in disease-resistant breeding, few studies on its molecular mechanism of disease resistance have been reported. To comprehensively study the mechanism of resistance to F. oxysporum, transcriptome sequencings of root tissues from Lilium pumilum inoculated with F. oxysporum or sterile water for 6, 12, or 24 h were performed. A total of 50 GB of data were obtained from the transcriptome sequencings of the 6 L. pumilum samples, and 217 098 Unigenes were obtained after the de novo assembly, of which 38.36% Unigenes were annotated. The sequencing results showed that the numbers of differentially expressed genes at 6, 12, and 24 h after inoculation compared with the control were 111, 254, and 2500, respectively. The functional enrichment analysis of the differentially expressed genes showed that several pathways were involved in responses of L. pumilum, mainly including starch and sucrose metabolism, glycolysis/gluconeogenesis, phenylpropanoid biosynthesis, plant hormone signal transduction, flavonoid biosynthesis, vitamin B6 (VB6) biosynthesis, acid biosynthesis, proteasome, and ribosome. Transcription factor analysis revealed that the WRKY and ERF families played important roles in responses of L. pumilum to F. oxysporum. The results of this study elucidate the molecular responses to F. oxysporum in lily and lay a theoretical foundation for improving lily breeding and strategies for lily basal rot resistance.
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This study aimed to use evolutionary psychology to explain conspicuous consumption's relationship with mating goals among women. We used experiments to show that power moderates conspicuous consumption's relationship with mating goals among women through an underlying relationship with women's social comparison tendencies. In Study 1, the participants read a passage describing a young woman wearing a coat made by a conspicuous brand (vs. an ordinary brand) who aimed to attract a desired man (vs. aiming to guard against potential competitors' attempts to disrupt her established intimate relationship). Participants in the conspicuous-brand condition were more confident that the young woman would succeed in mate attraction and guarding than participants in the ordinary-brand condition, suggesting the participants believed the conspicuous brands facilitated mate attraction and mate guarding more than ordinary brands. Study 2 manipulated the participants' power states and mating goals and measured participants' social comparison tendencies and conspicuous consumption index values. In the mate-guarding condition, high-power participants showed more inclination toward conspicuous consumption than low-power participants. In the mate-attraction condition, low-power participants showed a greater inclination toward conspicuous consumption than did high-power participants. Comparison orientation also mediated power's effect on conspicuous consumption inclination. The evolutionary psychological basis for the above findings is discussed, and suggestions are offered regarding product marketing.