3,637 research outputs found

    Fine structures of solar radio type III bursts and their possible relationship with coronal density turbulence

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    Solar radio type III bursts are believed to be the most sensitive signatures of near-relativistic electron beam propagation in the corona. A solar radio type IIIb-III pair burst with fine frequency structures, observed by the Low Frequency Array (LOFAR) with high temporal (~10 ms) and spectral (12.5 kHz) resolutions at 30–80 MHz, is presented. The observations show that the type III burst consists of many striae, which have a frequency scale of about 0.1 MHz in both the fundamental (plasma) and the harmonic (double plasma) emission. We investigate the effects of background density fluctuations based on the observation of striae structure to estimate the density perturbation in the solar corona. It is found that the spectral index of the density fluctuation spectrum is about −1.7, and the characteristic spatial scale of the density perturbation is around 700 km. This spectral index is very close to a Kolmogorov turbulence spectral index of −5/3, consistent with a turbulent cascade. This fact indicates that the coronal turbulence may play the important role of modulating the time structures of solar radio type III bursts, and the fine structure of radio type III bursts could provide a useful and unique tool to diagnose the turbulence in the solar corona

    Providing global public goods: Electoral delegation and cooperation

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    This paper experimentally examines the effect of electoral delegation on providing global public goods shared by several groups. Each group elects a delegate who can freely decide on each group member’s contribution (including the contribution of herself) to the global public good. Our results show that people mostly vote for delegates who assign equal contributions for every group member. However, in contrast to standard theoretical predictions, unequal contributions across groups drive cooperation down over time, and it decreases efficiency by almost 50% compared to the benchmark. This pattern is not driven by delegates trying to exploit their fellow group members, as indicated by the theory – quite to the opposite, other-regarding preferences and a re-election incentives guarantee that delegates assign equal contributions for all group members. Since the source of the resulting inefficiency is the polycentric nature of global public goods provision together with other-regarding preferences, we use the term Pinefficiency to describe our finding

    Consumption and savings of migrants in China – social cohesion perspective

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    Boosting domestic demand is the task of China’s sustainable economic development, and in particular, China has become an important global consumer market and the savings patterns should be more cohesive and without discriminations. Using data of China Migrants Dynamic Survey, the paper provides new evidence on internal migrants’ savings in China from the perspective of homeownership and family migration. We find that migrants’ savings are 5.25–6.60 percentage points higher than hukou population even when controlling for working, social status, and social insurance coverage which means the migrant will save 1019.88–1647.10 yuan in 2010 price more monthly. Furthermore, we discover housing could partly explain the saving gap, while when we take remittance and family migration into account, the saving rate differences between migrants and hukou population disappears, which means migrants may save to consume when they go back to their hometown with their family members instead of consuming later in the resident cities. The research is carried out taking into account the objectives of social cohesion policy identified at national and international level and their involvement in consumption and saving processes. Our empirical results reveal that homeownership, remittance motive and family migration play important roles in shaping saving behaviour of migrants

    Synthesis of Porous NiO and ZnO Submicro- and Nanofibers from Electrospun Polymer Fiber Templates

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    Porous nickel oxide (NiO) and zinc oxide (ZnO) submicro- and nanofibers were synthesized by impregnating electrospun polyacrylonitrile (PAN) fiber templates with corresponding metal nitrate aqueous solutions and subsequent calcination. The diameter of the NiO and ZnO fibers was closely related to that of the template fibers and larger diameters were obtained when using the template fibers with larger diameter. SEM results showed that the NiO and ZnO fibers have a large amount of pores with diameters ranging from 5 nm to 20 nm and 50 nm to 100 nm, respectively. Energy dispersive X-ray (EDX) spectra and X-ray diffraction (XRD) patterns testified that the obtained materials were NiO and ZnO with high purity

    A qualitative document analysis of policies influencing preeclampsia management by midwives in Ghana

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    Background: Preeclampsia is a global issue that causes significant morbidity and mortality in low- and middle-income countries (LMICs). The care women with preeclampsia receive in LMICs is below the standard experienced by women in westernised countries due to multiple interacting factors. A review of policy factors influencing the management of preeclampsia in Ghana is needed. Aim: This study focuses on the midwife\u27s role and scope of practice concerning preeclampsia management. The study aimed to explore the congruence between Ghanaian preeclampsia guidelines and international best practice recommendations for midwifery practice. The study also aimed to describe how recommendations are incorporated into Ghanaian guidelines. Method/design: This study was a qualitative document analysis of national and tertiary hospital policies related to midwives’ scope of practice in Ghana. Altheide\u27s five-step process (sampling, data collection, data coding and organisation, data analysis and report) was used to systematically source and analyse the content of written documents. Results: The findings illustrated several recommendation shortcomings in Ghanaian documents at the national and tertiary hospital levels. The content of Ghanaian preeclampsia management guidelines was not comprehensive, contained conflicting information, and was not backed by research evidence. The standards of practice for midwives were consistent at both the national and tertiary hospital levels. Midwives had limited roles in detection, management, stabilisation, and referral of women with preeclampsia. Conclusion: Uniform guidelines incorporating international recommendations are urgently needed to improve multi-professional collaboration, solidify midwives’ roles, and optimise maternal and fetal outcomes

    The Molecular Characterization of the Cyprinid herpesvirus 3 (CyHV-3) ORF24 Protein and its effect on the expression of immune genes (in vitro)

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    Cyprinid herpesvirus 3 (CyHV-3), known as koi herpesvirus (KHV), is highly contagious and lethal. In this study, we aimed to characterize the ORF24-encoding protein of CyHV-3, investigate its sub-cellular localization, and determine its impact on the expression of immune factors through in vitro experiments. The results showed that the CyHV-3 ORF24 protein comprises 579 amino acids. Interestingly, multiple comparisons with homologous proteins from three carp herpesvirus origins showed no significant similarity. The fluorescence localization experiment showed that the green fluorescence signal, representing the protein pEGFP-ORF24, was primarily diffused in the cytoplasm. Notably, the overexpression of ORF24 effectively suppressed the expression of immune factors in both CCO (Channel catfish ovary) and FHM (Fathead minnow muscle cell line) cells. Bioinformatic analysis indicated that the CyHV-3 ORF24 gene exhibited significant differences from the corresponding genes in the other two carp herpesviruses. This suggests its unique functional role in the evolutionary context. Moreover, our findings demonstrated that overexpression of CyHV-3 ORF24 can effectively inhibit the expression of immune factors, underscoring its crucial role as a viral immune escape factor. These results provide further insights into the immune function of the CyHV-3 ORF24 protein and offer a theoretical foundation for developing new vaccines against CyHV-3 virus infections
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