Influence of the Martian crustal magnetic fields on the Mars-solar wind interaction and plasma transport

The plasma transport process is important for the ionosphere of Mars, which controls the structure of the ionosphere above an altitude of 200 km. Plasma transport from the dayside ionosphere is crucial for producing the nightside ionosphere on Mars. The alteration in dayside plasma transport in the presence of crustal fields may influence the distribution of Martian ionospheric plasma and plasma escape in the magnetotail. This study employed a three-dimensional multispecies magnetohydrodynamic (MHD) model to simulate Mars-solar wind interactions. We show the magnetic field distribution and plasma velocity variation on the Martian day-side. The results indicate that the ion transport from low- to high-solar-zenith-angle areas in the south is inhibited by crustal fields, leading to a reduction in the ion number density and a thinner ionosphere near the southern terminator. Many heavy ions remain in the southern dayside ionosphere rather than moving to the nightside. In addition, the maximum reduction in the tailward flux of the planetary ions calculated by the MHD simulation is more than 50% at the southern terminator, indicating an inhibitory effect of the crustal fields on day-to-night transport. These effects may lead to a reduction in ion number density in the southern nightside ionosphere. Finally, we demonstrate a decrease in the global heavy-ion loss rate

Automatic Lumen Segmentation in Intravascular Optical Coherence Tomography Images Using Level Set

<p> Automatic lumen segmentation from intravascular optical coherence tomography (IVOCT) images is an important and fundamental work for diagnosis and treatment of coronary artery disease. However, it is a very challenging task due to irregular lumen caused by unstable plaque and bifurcation vessel, guide wire shadow, and blood artifacts. To address these problems, this paper presents a novel automatic level set based segmentation algorithm which is very competent for irregular lumen challenge. Before applying the level set model, a narrow image smooth filter is proposed to reduce the effect of artifacts and prevent the leakage of level set meanwhile. Moreover, a divide-and-conquer strategy is proposed to deal with the guide wire shadow. With our proposed method, the influence of irregular lumen, guide wire shadow, and blood artifacts can be appreciably reduced. Finally, the experimental results showed that the proposed method is robust and accurate by evaluating 880 images from 5 different patients and the average DSC value was 98.1% +/- 1.1%.</p

Effects of solar wind density and velocity variations on the Martian ionosphere and plasma transport - a MHD model study

Solar wind dynamic pressure, consisting solar wind density and velocity , is an important external driver that controls Martian plasma environment. In this study, a 3D magnetohydrodynamic model is applied to investigate the separate influences of solar wind density and velocity on the Martian ionosphere. The spatial distributions of ions in the dayside and near nightside ionosphere under different and are analyzed, as well as the ion transport process. We find that for the same dynamic pressure condition, the ionosphere extends to higher altitudes under higher solar wind density, indicating that a solar wind velocity enhancement event is more efficient at compressing the Martian ionosphere. A higher will result in a stronger induced magnetic field, shielding the Martian ionosphere, preventing the penetration of solar wind particles. For the same dynamic pressure, increasing (decreasing ) leads to a higher horizontal ion velocity, facilitating day-to-night plasma transport. As a result, the ionosphere extends farther into the nightside. Also, the ion outflow flux is larger for high , which may lead to a higher escape rate. Moreover, the strong crustal fields in the southern hemisphere also cause significant effect to the ionosphere, hindering horizontal ion transport. An additional outflow channel is also provided by the crustal field on the southern dayside, causing different responses of flow pattern between local and global scale while the solar wind condition is varied

Integrative transcriptomic profiling of mRNA, miRNA, circRNA, and lncRNA in alveolar macrophages isolated from PRRSV-infected porcine

IntroductionThe porcine reproductive and respiratory syndrome virus (PRRSV) continues to pose a significant threat to the global swine industry, attributed largely to its immunosuppressive properties and the chronic nature of its infection. The absence of effective vaccines and therapeutics amplifies the urgency to deepen our comprehension of PRRSV’s intricate pathogenic mechanisms. Previous transcriptomic studies, although informative, are partially constrained by their predominant reliance on in vitro models or lack of long-term infections. Moreover, the role of circular RNAs (circRNAs) during PRRSV invasion is yet to be elucidated.MethodsIn this study, we employed an in vivo approach, exposing piglets to a PRRSV challenge over varied durations of 3, 7, or 21 days. Subsequently, porcine alveolar macrophages were isolated for a comprehensive transcriptomic investigation, examining the expression patterns of mRNAs, miRNAs, circRNAs, and long non-coding RNAs (lncRNAs).ResultsDifferentially expressed RNAs from all four categories were identified, underscoring the dynamic interplay among these RNA species during PRRSV infection. Functional enrichment analyses indicate that these differentially expressed RNAs, as well as their target genes, play a pivotal role in immune related pathways. For the first time, we integrated circRNAs into the lncRNA-miRNA-mRNA relationship, constructing a competitive endogenous RNA (ceRNA) network. Our findings highlight the immune-related genes, CTLA4 and SAMHD1, as well as their associated miRNAs, lncRNAs, and circRNAs, suggesting potential therapeutic targets for PRRS. Importantly, we corroborated the expression patterns of selected RNAs through RT-qPCR, ensuring consistency with our transcriptomic sequencing data.DiscussionThis study sheds lights on the intricate RNA interplay during PRRSV infection and provides a solid foundation for future therapeutic strategizing

A new integrated and homogenized global monthly land surface air temperature dataset for the period since 1900

A new dataset of integrated and homogenized monthly surface air temperature over global land for the period since 1900 [China Meteorological Administration global Land Surface Air Temperature (CMA-LSAT)] is developed. In total, 14 sources have been collected and integrated into the newly developed dataset, including three global (CRUTEM4, GHCN, and BEST), three regional and eight national sources. Duplicate stations are identified, and those with the higher priority are chosen or spliced. Then, a consistency test and a climate outlier test are conducted to ensure that each station series is quality controlled. Next, two steps are adopted to assure the homogeneity of the station series: (1) homogenized station series in existing national datasets (by National Meteorological Services) are directly integrated into the dataset without any changes (50% of all stations), and (2) the inhomogeneities are detected and adjusted for in the remaining data series using a penalized maximal t test (50% of all stations). Based on the dataset, we re-assess the temperature changes in global and regional areas compared with GHCN-V3 and CRUTEM4, as well as the temperature changes during the three periods of 1900–2014, 1979–2014 and 1998–2014. The best estimates of warming trends and there 95% confidence ranges for 1900–2014 are approximately 0.102 ± 0.006 °C/decade for the whole year, and 0.104 ± 0.009, 0.112 ± 0.007, 0.090 ± 0.006, and 0.092 ± 0.007 °C/decade for the DJF (December, January, February), MAM, JJA, and SON seasons, respectively. MAM saw the most significant warming trend in both 1900–2014 and 1979–2014. For an even shorter and more recent period (1998–2014), MAM, JJA and SON show similar warming trends, while DJF shows opposite trends. The results show that the ability of CMA-LAST for describing the global temperature changes is similar with other existing products, while there are some differences when describing regional temperature changes

Essays on education economics and policy

Education plays an important role in knowledge acquisition and technological progress. For instance, higher educational attainment positively affects innovation and technology transfer in OECD countries (Griffith et al., 2004). Highly-educated workers are more likely to adapt new technologies to innovation, increasing a country’s long-run productivity growth (Howitt et al., 2004). Among various factors affecting the quality of education, language plays an important role in communication and knowledge transfer. For instance, as English becomes the dominant language in scientific knowledge and academia globally, non-native English-speaking scholars might face greater challenges in publishing high-quality articles in English, due to lower English proficiency. Such language barriers might impede global talent mobility in academia. For instance, top researchers might prefer staying in their home universities, as they could communicate in native language. To understand how language-related educational policies affect academic outputs, this dissertation focuses on causal impacts and the relevant mechanisms that drive such impacts. In particular, chapter (1) asks how language distance to English affects university research performance, chapter (2) asks how switching the language of instruction to English affects university academic ability of newly-hired international staff, and chapter (3) asks how an objective entry standard in educational selection brings unequal access to disadvantaged students. The empirical results show that language distance to English negatively affects research performance of non-native English-speaking universities. It also indicates that switching the language of instruction to English positively affects academic ability of universities’ newly-hired international staff. It further implies that setting an objective entry standard in educational tracking brings unequal access to disadvantaged students. This dissertation implies that language distance to English generates barriers to scientific communication and academic outputs for non-native English-speaking scholars. Switching to English as the language of instruction allows universities to recruit international faculty with higher academic ability. This might remove language barriers and increase global talent mobility. This dissertation contributes to the debate on the measurement of international rankings, and the factors that influence universities’ performance in rankings. For instance, De Witte and Hudrlikova (2013) show that in general, universities in English-speaking countries benefit from existing rankings. Non-native English-speaking universities might underperform in citationbased international rankings due to fewer citations in non-English journal articles (T. Van Raan et al., 2011). Hazelkorn (2007) indicates that international rankings play an important role in universities’ decision-making process. By showing language distance to English negatively affects universities’ research performance in rankings, this dissertation suggests policy makers take the role of language into account when applying international rankings. This dissertation contributes to the literature on potential hurdles to talent mobility and knowledge diffusion. For instance, travel visa restrictions, border restrictions, and immigration policy barriers might negatively affect international talent mobility and knowledge diffusion (Appelt et al., 2015; Orazbayev, 2017). Malik (2013) indicates a negative relationship between language barriers and technology transfer. Similarly, MacGarvie (2005) implies that common language would increase the speed of technological knowledge diffusion. By showing that switching to English as the language of instruction positively affects universities’ academic ability of newly-hired international staff, this dissertation implies that switching to the lingua franca would remove language hurdle to global talent mobility and increase the speed of knowledge diffusion. It suggests educators and policy makers consider language as a strategic choice to attract global talents. This dissertation also broadly relates to the endogenous growth theory. Aghion et al. (1998) argue that the long-run economic growth depends on human capital, knowledge spillover, and innovation. Policy makers should consider the role of education in a technological environment (Howitt et al., 2004). This dissertation implies that language-related policies significantly affects talent mobility, knowledge diffusion, and long-run research productivity in higher education. It also implies how selection standards might affect ability distribution and long-run productivity, and the importance of taking individual disadvantages into account when setting selection criteria in education.</p

Initial changes in alveolar bone volume for sham-operated and ovariectomized rats in ligature-induced experimental periodontitis.

OBJECTIVES Osteoporosis is a disease characterized by a reduction in bone mass, poor bone strength, and microarchitectural deterioration primarily in postmenopausal women. With respect to periodontal disease, osteoporosis is thought to contribute to pre-existing alveolar degeneration although the association between both diseases is not fully characterized. The aim of the present study was to observe the initial changes in mandibular alveolar bone for sham-operated and ovariectomized (OVX) rats in ligature-induced experimental periodontitis. MATERIALS AND METHODS A total of 64 Wistar rats (7 weeks of age, 180-200 g) were used in this study (32 control sham-operated animals + ligature placement, 32 OVX animals + ligature placement). Following an 8-week period to induce an OVX model, micro-CT analysis was performed to calculate vertical and furcation bone loss of mandibular first molars at time points 0, 3, 7, and 11 days following ligature placement (six animals per group per time point). Furthermore, histological analysis was performed to calculate the loss of alveolar bone crest height from the cemento-enamel junction, and tartrate-resistant acid phosphatase (TRAP) staining was utilized to calculate the number of osteoclasts. RESULTS The results from the present study demonstrate that OVX animals showed significant vertical bone loss at all time points when compared to control sham-operated animals. In the furcation area, no significant difference in bone loss was observed between sham-operated and OVX animals at 0, 3, and 7 days; however by 11 days, a significant decrease in bone volume/total volume and trabecular thickness was observed in the OVX group. The histological analysis also revealed that alveolar bone crest height was significantly reduced in OVX animals, and TRAP staining further revealed the greater number of multinucleated osteoclasts peaking at 3 days postligature placement. CONCLUSION The results from the present study demonstrate a direct correlation between the osteoporotic phenotype and the progression of periodontal breakdown in a diseased-induced animal model. CLINICAL RELEVANCE It may be suggested that an osteoporotic phenotype has the potential to speed periodontal breakdown and thus contributes to the overall degeneration of the periodontium in patients suffering from postmenopausal bone loss. Future research from human clinical studies are necessary to further understand the relationship between periodontal disease and osteoporosis

Recent Technical Advances in Accelerating the Clinical Translation of Small Animal Brain Imaging: Hybrid Imaging, Deep Learning, and Transcriptomics

Small animal models play a fundamental role in brain research by deepening the understanding of the physiological functions and mechanisms underlying brain disorders and are thus essential in the development of therapeutic and diagnostic imaging tracers targeting the central nervous system. Advances in structural, functional, and molecular imaging using MRI, PET, fluorescence imaging, and optoacoustic imaging have enabled the interrogation of the rodent brain across a large temporal and spatial resolution scale in a non-invasively manner. However, there are still several major gaps in translating from preclinical brain imaging to the clinical setting. The hindering factors include the following: (1) intrinsic differences between biological species regarding brain size, cell type, protein expression level, and metabolism level and (2) imaging technical barriers regarding the interpretation of image contrast and limited spatiotemporal resolution. To mitigate these factors, single-cell transcriptomics and measures to identify the cellular source of PET tracers have been developed. Meanwhile, hybrid imaging techniques that provide highly complementary anatomical and molecular information are emerging. Furthermore, deep learning-based image analysis has been developed to enhance the quantification and optimization of the imaging protocol. In this mini-review, we summarize the recent developments in small animal neuroimaging toward improved translational power, with a focus on technical improvement including hybrid imaging, data processing, transcriptomics, awake animal imaging, and on-chip pharmacokinetics. We also discuss outstanding challenges in standardization and considerations toward increasing translational power and propose future outlooks.ISSN:2296-858