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We report on experimental detection of the spin-orbit interaction field in an InAs nanowire double quantum dot device. In the spin blockade regime, leakage current through the double quantum dot is measured and is used to extract the effects of spin-orbit interaction and hyperfine interaction on spin state mixing. At finite magnetic fields, the leakage current arising from the hyperfine interaction can be suppressed, and the spin-orbit interaction dominates spin state mixing. We observe dependence of the leakage current on the applied magnetic field direction and determine the direction of the spin-orbit interaction field. We show that the spin-orbit field lies in a direction perpendicular to the nanowire axis but with a pronounced off-substrate-plane angle. The results are expected to have an important implication in employing InAs nanowires to construct spin-orbit qubits and topological quantum devices.
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This paper applies a structural equation model (SEM) to analyze the formation of awareness and perception of water scarcity, based on a cross-sectional dataset of 446 farmers in the Guanzhong Plain, Shaanxi Province, China. We find that age, percentage of time spent on farming and social network are the main determinants of awareness. Water price and drought experience are the most important explanatory variables of perception. In addition, awareness and perception strongly interact. The results obtained in this paper are relevant for policymaking, since environmental behavior, which includes efficient use of natural resources, tends to improve if supported by internalization of social norms, which in its turn, is promoted by awareness and perception. From the analysis it follows that spreading information via social networks, rather than via the media, is an important vehicle to enhance awareness and perception and thus to improve irrigation water use efficiency. Special attention should be paid to part-time farmers who are limited in directly perceiving water scarcity. Finally, more use should be made of the price mechanism to strengthen perception and awareness.
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Modelos Teóricos , Opinião Pública , População Rural , Abastecimento de Água , Adulto , Fatores Etários , Idoso , Irrigação Agrícola/economia , Agricultura , Atitude , Conscientização , China , Coleta de Dados , Secas , Humanos , Pessoa de Meia-Idade , Formulação de Políticas , Apoio Social , Fatores SocioeconômicosRESUMO
Tropical cyclones drive coastal ecosystem dynamics, and their frequency, intensity, and spatial distribution are predicted to shift with climate change. Patterns of resistance and resilience were synthesized for 4138 ecosystem time series from n = 26 storms occurring between 1985 and 2018 in the Northern Hemisphere to predict how coastal ecosystems will respond to future disturbance regimes. Data were grouped by ecosystems (fresh water, salt water, terrestrial, and wetland) and response categories (biogeochemistry, hydrography, mobile biota, sedentary fauna, and vascular plants). We observed a repeated pattern of trade-offs between resistance and resilience across analyses. These patterns are likely the outcomes of evolutionary adaptation, they conform to disturbance theories, and they indicate that consistent rules may govern ecosystem susceptibility to tropical cyclones.
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We apply multivariate statistics to explore the large data sets encountered from Fourier transform ion cyclotron resonance mass spectra of dissolved organic matter (DOM). Molecular formula assignments for the individual constituents of DOM are examined by hierarchal cluster analysis (HCA) and principal component analysis (PCA), to measure the relationships between numerous DOM samples. We compare two approaches: (1) using averages of elemental ratios and double bond equivalents calculated from the formulas, and (2) employing individual formulas and either their presence/absence or relative magnitude in each sample. With approach 2, PCA deciphers which of the thousands of formulas are significant to particular samples, and then a van Krevelen diagram highlights what types of compounds are molecular signatures to the samples. Our dual approach, especially approach 2, allows for complex data sets to be more easily interpreted, aiding in the characterization of DOM from various sources. By applying this methodology, clear trends can be delineated, trends that are not apparent from currently employed methods. Terrestrial DOM contains various lignin-derived compounds, tannins, and condensed aromatics. Marine DOM contains aliphatic compounds with heteroatom functionalities, as well as lignin-like molecules.
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Espectrometria de Massas/métodos , Análise por Conglomerados , Análise de Fourier , Análise de Componente PrincipalRESUMO
This paper applies a structural equation modeling approach to study the formation of consumers' perceived health risk of genetically modified (GM) foods based on a cross-sectional dataset of 508 consumers in Xi'an, China. The results indicate a high percentage of respondents who believe that GM foods might threaten human health. The estimated structural equation model shows that males, older people, respondents with higher income, those with better educational attainment, and those with family members who need special care have higher perceived risks of GM foods. Effective risk communication is necessary to provide consumers with scientific information about GM foods in order to facilitate their understanding of the actual risks of GM foods.
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Alimentos Geneticamente Modificados , Conhecimentos, Atitudes e Prática em Saúde , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , China , Estudos Transversais , Feminino , Humanos , Análise de Classes Latentes , Masculino , Pessoa de Meia-Idade , Modelos Teóricos , Percepção , Adulto JovemRESUMO
The transport characteristics of a disordered, multilayered MoS2 nanoflake in the insulator regime are studied by electrical and magnetotransport measurements. The MoS2 nanoflake is exfoliated from a bulk MoS2 crystal and the conductance G and magnetoresistance are measured in a four-probe setup over a wide range of temperatures. At high temperatures, we observe that ln G exhibits a -T -1 temperature dependence and the transport in the nanoflake dominantly arises from thermal activation. At low temperatures, where the transport in the nanoflake dominantly takes place via variable-range hopping (VRH) processes, we observe that ln G exhibits a -T -1/3 temperature dependence, an evidence for the two-dimensional (2D) Mott VRH transport. Furthermore, we observe that the measured low-field magnetoresistance of the nanoflake in the insulator regime exhibits a quadratic magnetic field dependence â¼ αB 2 with α â¼ T -1, fully consistent with the 2D Mott VRH transport in the nanoflake.
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There has been evidence demonstrating that China has had a persistently low and below-replacement level fertility since early 1990s, causing concerns of a rapidly aging population and sustainability of the Chinese economy. To avoid adverse effects of excessively low fertility, the Chinese government has recently changed its family planning policy from "one-child policy" to "two-child policy." Nonetheless, the effectiveness of the newly initiated two-child policy is questionable if women's average desired number of children or desired fertility for their lifetime is below the threshold fertility allowed by the two-child policy. Therefore, this study argues that it would be interesting and pertinent to know women's fertility desires under the circumstances of no policy restrictions and understand major factors that may affect their desired fertility. Based on a multi-stage stratified cluster sampling survey with 2,516 women respondents in rural Shaanxi, this study tries to estimate desired fertility of rural women and evaluate the impact of important socioeconomic factors on their desired fertility. The results of this study reveal that the average lifetime desired fertility for rural women of childbearing age in Shaanxi is about 1.71, below the total fertility rate at the replacement level. The findings of this study suggest that women's marriage age, the pecuniary costs of having children, women's income forgone for having children, and social security benefits available for rural residents at retirement age, are significantly and negatively related to desired fertility. However, rural women's cultural views towards fertility are significantly but positively related to their desired fertility. This study further confirms that China has entered an era of low fertility, and thus, any policy restrictions on fertility may no longer be necessary. Instead, government programs which support childbearing and childrearing are needed to prevent excessive low fertility and rapid aging of the population.
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Comportamento Reprodutivo/psicologia , Adulto , China , Cultura , Política de Planejamento Familiar , Feminino , Fertilidade , Humanos , Casamento , Comportamento Materno/psicologia , Modelos Econômicos , Motivação , População Rural , Previdência Social , Fatores SocioeconômicosRESUMO
Studies on the perception of air pollution in China are very limited. The aim of this paper is to help to fill this gap by analyzing a cross-sectional dataset of 759 residents of the Jinchuan mining area, Gansu Province, China. The estimations suggest that perception of air pollution is two-dimensional. The first dimension is the perceived intensity of air pollution and the second is the perceived hazardousness of the pollutants. Both dimensions are influenced by environmental knowledge. Perceived intensity is furthermore influenced by socio-economic status and proximity to the pollution source; perceived hazardousness is influenced by socio-economic status, family health experience, family size and proximity to the pollution source. There are no reverse effects from perception on environmental knowledge. The main conclusion is that virtually all Jinchuan residents perceive high intensity and hazardousness of air pollution despite the fact that public information on air pollution and its health impacts is classified to a great extent. It is suggested that, to assist the residents to take appropriate preventive action, the local government should develop counseling and educational campaigns and institutionalize disclosure of air quality conditions. These programs should pay special attention to young residents who have limited knowledge of air pollution in the Jinchuan mining area.
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Poluição do Ar , Modelos Teóricos , Percepção , Adulto , Idoso , Idoso de 80 Anos ou mais , China , Poluição Ambiental , Humanos , Pessoa de Meia-Idade , Mineração , Adulto JovemRESUMO
BACKGROUND: There is evidence that household air pollution is associated with poor health in China, and that this form of air pollution may even be more of a health concern in China than the much-publicized outdoor air pollution. However, there is little empirical evidence on the relationship between household air pollution and health in China based on nationally representative and longitudinal data. This study examines the association between the type of domestic cooking fuel and the health of women aged ≥16 in rural China. METHODS: Using longitudinal and biomarker data from the China Family Panel Studies (n = 12,901) and the China Health and Nutrition Survey (n = 15,539), we investigate the impact of three major domestic cooking fuels (wood/straw, coal, liquefied petroleum gas (LPG)) on health status using both cross-sectional and panel approaches. RESULTS: Compared to women whose households cook with dirty fuels like wood/straw, women whose households cook with cleaner fuels like LPG have a significantly lower probability of chronic or acute diseases and are more likely to report better health. Cooking with domestic coal instead of wood or straw is also associated with elevated levels of having certain risks (such as systolic blood pressure) related to cardiovascular diseases. CONCLUSIONS: Our study provides evidence that using cleaner fuels like LPG is associated with better health among women in rural China, suggesting that the shift from dirty fuels to cleaner choices may be associated with improved health outcomes.
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Poluição do Ar em Ambientes Fechados/efeitos adversos , Culinária , Saúde da Mulher , Adulto , Poluição do Ar , China , Carvão Mineral , Estudos Transversais , Características da Família , Feminino , Nível de Saúde , Humanos , Pessoa de Meia-Idade , Petróleo , Risco , População Rural , MadeiraRESUMO
Continental margin systems are important contributors to global nutrient and carbon budgets. Effort is needed to quantify this contribution and how it will be modified under changing patterns of climate and land use. Coupled models will be used to provide projections of future states of continental margin systems. Thus, it is appropriate to consider the limitations that impede the development of realistic models. Here, we provide an overview of the current state of modeling carbon cycling on continental margins as well as the processes and issues that provide the next challenges to such models. Our overview is done within the context of a coupled circulation-biogeochemical model developed for the northeastern North American continental shelf region. Particular choices of forcing and initial fields and process parameterizations are used to illustrate the consequences for simulated distributions, as revealed by comparisons to observations using quantitative statistical metrics.