9 research outputs found
The Volumetric Extended-Schmidt Law: A Unity Slope
We investigate the extended-Schmidt (ES) law in volume densities ( ) for
spatially-resolved regions in spiral, dwarf, and ultra-diffuse galaxies (UDGs),
and compare to the volumetric Kennicutt-Schmidt (KS) law (
). We first characterize these
star formation laws in individual galaxies using a sample of 11 spirals,
finding median slopes =0.98 and =1.42, with
a galaxy-to-galaxy rms fluctuation that is substantially smaller for the
volumetric ES law (0.18 vs 0.41). By combining all regions in spirals with
those in additional 13 dwarfs and one UDG into one single dataset, it is found
that the rms scatter of the volumetric ES law at given x-axis is 0.25 dex, also
smaller than that of the volumetric KS law (0.34 dex). At the extremely low gas
density regime as offered by the UDG, the volumetric KS law breaks down but the
volumetric ES law still holds. On the other hand, as compared to the surface
density ES law, the volumetric ES law instead has a slightly larger rms
scatter, consistent with the scenario that the ES law has an intrinsic slope of
1 but the additional observational error of the scale
height increases the uncertainty of the volume density. The unity slope of the
ES law implies that the star formation efficiency (=/) is regulated by the quantity that is related to the .Comment: 15 pages, 8 figures, accepted by MNRA
The \ion{H}{I}-rich Ultra-diffuse Galaxies follow the Extended Schmidt Law
The \ion{H}{I}-rich ultra-diffuse galaxies (HUDGs) offer a unique case for
studies of star formation laws (SFLs) as they host low star formation
efficiency (SFE) and low-metallicity environments where gas is predominantly
atomic. We collect a sample of six HUDGs in the field and investigate their
location in the extended Schmidt law(). They are
consistent with this relationship well (with deviations of only 1.1 sigma).
Furthermore, we find that HUDGs follow the tight correlation between the
hydrostatic pressure in the galaxy mid-plane and the quantity on the x-axis
() of the extended Schmidt law. This
result indicates that these HUDGs can be self-regulated systems that reach the
dynamical and thermal equilibrium. In this framework, the stellar gravity
compresses the disk vertically and counteracts the gas pressure in the galaxy
mid-plane to regulate the star formation as suggested by some theoretical
models.Comment: 6 pages, 4 figures, accepted for publication in MNRA
Childhood Influenza Vaccination and Its Determinants during 2020-2021 Flu Seasons in China: A Cross-Sectional Survey.
Young children aged 6−59 months are recommended as one of the priority groups for seasonal influenza vaccination in China. This study assessed influenza vaccination coverage and the factors associated with vaccination uptake among children in three Chinese provinces. In September 2021, 2081 caregivers with children <5 years completed self-administered questionnaires as part of a cross-sectional survey. Logistic regression was used to assess determinants of childhood influenza vaccination. A total of 43.63% of respondents reported vaccinating their children against influenza during the 2020−2021 flu season. Caregivers who lived in Anhui province, had a bachelor degree or above, and an annual household income <20,000 RMB were more likely to vaccinate their children against influenza. Confidence in the importance (OR: 2.50; 95%CI: 1.77−3.54), safety (OR: 1.60; 95%CI: 1.29−1.99), and effectiveness (OR: 1.54; 95%CI: 1.23−1.93) of influenza vaccine was significantly associated with childhood vaccine acceptance. Respondents who saw that other caregivers were vaccinating their children had significantly higher odds of vaccinating their own children. Caregivers’ receiving positive influence from healthcare workers (OR: 1.33; 95%CI: 1.00−1.77), family members, or friends (OR: 1.30; 95%CI: 1.14−1.49) were also significantly associated with childhood influenza vaccination. Poor access, including conflicts between caregivers’ availability and vaccination service schedules and inconvenient transportation to the vaccination site were negatively associated with childhood flu vaccination. To promote childhood influenza vaccination, public health information campaigns need to target wealthier and less educated caregivers to enhance caregivers’ confidence in influenza vaccination. Targeted interventions are also needed to optimize access to vaccination services, including extending vaccination service hours and increasing the number of vaccination sites close to residential areas. Interventions are also needed to encourage primary care providers to play a greater role in promoting vaccination. Finally, the dissemination of related information and the public response need to be monitored for the timely understanding of public perceptions
The determinants of vaccine hesitancy in China: A cross-sectional study following the Changchun Changsheng vaccine incident.
INTRODUCTION: Vaccine hesitancy is cited as one of the top threats to global health. The Changchun Changsheng Biotechnology Company was found to have violated good manufacturing practices in July 2018, leading to widespread distribution of sub-potent vaccines in China. We estimated the prevalence and determinants of vaccine hesitancy following the Changchun Changsheng vaccine incident (CCVI). METHODS: We conducted a cross-sectional survey in China in January 2019, and 2,124 caregivers of children < 6 years old completed self-administered questionnaires. Multinomial logistic regression was used to assess the determinants of vaccine hesitancy; the potential determinants included demographics, socioeconomic status, vaccine confidence, and knowledge of the CCVI. Adjusted Odds Ratios (AORs) and 95% confidence intervals (CI) are reported. RESULTS: Around 89% of caregivers had heard of the CCVI. Although 83% and 88% of caregivers agreed that vaccines are safe and effective, respectively, 60% expressed some hesitancy about vaccination. Of those hesitant, 26% vaccinated their children at times with doubts, 31% delayed vaccination and 3% refused specific vaccines. Multinomial regression analysis showed that confidence in vaccine safety was associated with a reduced odds of doubts on vaccination (AOR = 0.64; 95%CI = 0.44-0.94), whereas caregivers who had heard of the CCVI had a significantly higher odds of doubts on vaccination (AOR = 1.61; 95%CI = 1.05-2.45). Confidence in the vaccine delivery system and government were associated with a lower odds of vaccine hesitancy. Caregivers with higher education and Buddhism or other religions were significantly more hesitant to vaccinate their children. CONCLUSION: Vaccine hesitancy was prevalent following the CCVI. Over half the caregivers either accepted childhood vaccination with doubts or delayed vaccines; only a small number were active refusers. Our findings highlight the importance of addressing vaccine hesitancy, especially following vaccine incidents. Tailored communications are needed to reduce vaccine hesitancy, especially among the highly educated and Buddhist caregivers
Access to Vaccination Information and Confidence/Hesitancy Towards Childhood Vaccination: A Cross-Sectional Survey in China.
Access to vaccination information could influence public attitudes towards vaccination. This study investigated the number and types of vaccination-related information sources, and estimated their associations with vaccine confidence and hesitancy in China. In January 2019, we conducted a cross-sectional survey in China, and 2122 caregivers with children <6 years completed self-administered questionnaires. Logistic regressions were used to assess associations between caregivers' primary information sources and vaccine confidence/hesitancy. A majority (72%) of caregivers had multiple sources of vaccination-related information. The proportions of caregivers reporting professional sources, media, and peers as primary information sources were 81%, 63%, and 26%. Internal migrants were less likely to get information from professional sources; more educated and wealthier caregivers reported more information sources and were more likely to get information from media and peers. Caregivers who reported professional information sources had significantly higher odds of being confident about the safety of vaccines and lower odds of being hesitant toward vaccination than those who did not. Caregivers who reported the media as a primary information source had significantly higher odds of being hesitant toward vaccination than those who did not. To address vaccine hesitancy, it is essential to promote universal access to professional vaccination-related information sources, and to use the media to disseminate evidence-based information and clarify misinformation. Health communication should target internal migrants, and more educated and wealthier caregivers
A Robust Near-Infrared Calibration Model for the Determination of Chlorophyll Concentration in Tree Leaves with a Calibration Transfer Method
<div><p>A method based on piecewise direct standardization was developed to directly predict leaf chlorophyll concentrations by correction of near-infrared spectra to construct a robust calibration model. Chinar, camphor, and gingko leaves collected from two growth intervals were evaluated. Spectral pretreatment methods and wavelength selection were investigated. The first derivative combined with stability competitive adaptive reweighted sampling before piecewise direct standardization provided the best performance. Under the optimized parameters, the root mean square error of prediction was significantly reduced by using piecewise direct standardization. This study demonstrates that the calibration model may be used to rapidly characterize chlorophyll concentrations across species and growth intervals.</p></div