On χ−\chi-slice pretzel links

A link is called $\chi-$slice if it bounds a smooth properly embedded surface in the 4-ball with no closed components and Euler characteristic 1. If a link has a single component, then it is $\chi-$slice if and only if it is slice. One motivation for studying such links is that the double cover of the 3-sphere branched along a nonzero determinant $\chi-$slice link is a rational homology 3-sphere that bounds a rational homology 4-ball. This article aims to generalize known results about the sliceness of pretzel knots to the $\chi-$sliceness of pretzel links. In particular, we completely classify positive and negative pretzel links that are $\chi-$slice, and obtain partial classifications of 3-stranded and 4-stranded pretzel links that are $\chi-$slice. As a consequence, we obtain infinite families of Seifert fiber spaces that bound rational homology 4-balls

VODKA-JWST: A 3.8 kpc dual quasar at cosmic noon in a powerful starburst galaxy with JWST/MIRI IFU

Dual quasars, two active supermassive black holes at galactic scales, represent crucial objects for studying the impact of galaxy mergers and quasar activity on the star formation rate (SFR) within their host galaxies, particularly at cosmic noon when SFR peaks. We present JWST/MIRI mid-infrared integral field spectroscopy of J074922.96+225511.7, a dual quasar with a projected separation of 3.8 kilo-parsec at a redshift $z$ of 2.17. We detect spatially extended [Fe II] 5.34$\rm \mu$m and polycyclic aromatic hydrocarbon (PAH) 3.3$\mu$m emissions from the star formation activity in its host galaxy. We derive the SFR of 10$^{3.0\pm0.2}$ M$_{\odot}$ yr$^{-1}$ using PAH 3.3$\mu$m, which is five times higher than that derived from the cutoff luminosity of the infrared luminosity function for galaxies at $z\sim2$. While the SFR of J0749+2255 agrees with that of star-forming galaxies of comparable stellar mass at the same redshifts, its molecular gas content falls short of expectations based on the molecular Kennicutt-Schmidt law. This discrepancy may result from molecular gas depletion due to the longer elevated stage of star formation, even after the molecular gas reservoir is depleted. We do not observe any quasar-driven outflow that impacts PAH and [Fe II] in the host galaxy based on the spatially resolved maps. From the expected flux in PAH-based star formation, the [Fe II] line likely originates from the star-forming regions in the host galaxy. Our study highlights the stardust nature of J0749+2255, indicating a potential connection between the dual quasar phase and intense star formation activities.Comment: 12 pages, 7 figures, 1 table, submitted to ApJ, comments are welcom

A SPectroscopic Survey of Biased Halos in the Reionization Era (ASPIRE): A First Look at the Rest-frame Optical Spectra of z > 6.5 Quasars Using JWST

© 2023. The Author(s). Published by the American Astronomical Society. This is an open access article distributed under the Creative Commons Attribution License, to view a copy of the license, see: https://creativecommons.org/licenses/by/4.0/Studies of rest-frame optical emission in quasars at z > 6 have historically been limited by the wavelengths accessible by ground-based telescopes. The James Webb Space Telescope (JWST) now offers the opportunity to probe this emission deep into the reionization epoch. We report the observations of eight quasars at z > 6.5 using the JWST/NIRCam Wide Field Slitless Spectroscopy as a part of the “A SPectroscopic survey of biased halos In the Reionization Era (ASPIRE)” program. Our JWST spectra cover the quasars’ emission between rest frame ∼4100 and 5100 Å. The profiles of these quasars’ broad Hβ emission lines span a full width at half maximum from 3000 to 6000 km s−1. The Hβ-based virial black hole (BH) masses, ranging from 0.6 to 2.1 billion solar masses, are generally consistent with their Mg ii-based BH masses. The new measurements based on the more reliable Hβ tracer thus confirm the existence of a billion solar-mass BHs in the reionization epoch. In the observed [O iii] λ λ 4960,5008 doublets of these luminous quasars, broad components are more common than narrow core components (≤ 1200 km s−1), and only one quasar shows stronger narrow components than broad. Two quasars exhibit significantly broad and blueshifted [O iii] emission, thought to trace galactic-scale outflows, with median velocities of −610 and −1430 km s−1 relative to the [C ii] 158 μm line. All eight quasars show strong optical Fe ii emission and follow the eigenvector 1 relations defined by low-redshift quasars. The entire ASPIRE program will eventually cover 25 quasars and provide a statistical sample for the studies of the BHs and quasar spectral properties.Peer reviewe

A note on knot Floer homology of satellite knots with (1,1)-patterns

We prove that if $P$ is a $(1,1)$-pattern knot, the two inequalities $\dim \widehat{HFK} (P(K)) \geqslant \dim \widehat{HFK} (P(U))$ and $\dim \widehat{HFK} (P(K)) \geqslant \dim \widehat{HFK} (K)$ hold for the unknot $U\subset S^3$ and any companion knot $K\subset S^3$.Comment: 11 pages, 9 figures. Comments welcomed

Art Culture and Fractal Dimension

The objective of this project was to quantify the relationship between art and culture through the computation of fractal dimensions of major artworks. To this end, we computed the fractal dimensions of the masterpieces from the East and West and also explored the difference between male and female painters. We found out that the fractal dimension of these paintings is correlated closely with the artist career and the prevailing culture

Quasiconformal Gradient Flows

The objective of this project was to quantify the difference between two planar domains with finitely prescribed matching points. To this end, we use gradient flows to obtain a homotopy of quasiconformal mappings between the two shapes, find a canonical minimizer for maximal infinitesimal stretching and rotation, and take the distortion of the minimizer as a measure of the difference between the two planar shapes. In our approach, numerical implementation is applied to get better insight of the long-time behavior of the gradient flow

A retrospective epidemiological analysis of human Cryptosporidium infection in China during the past three decades (1987-2018).

BackgroundCryptosporidiosis is an emerging infectious disease of public health significance worldwide. The burden of disease caused by Cryptosporidium varies between and within countries/areas. To have a comprehensive understanding of epidemiological status and characteristics of human Cryptosporidium infection in China since the first report in 1987, a retrospective epidemiological analysis was conducted by presenting differences in the prevalence of Cryptosporidium by province, year, population, living environment and season and possible transmission routes and risk factors as well as genetic characteristics of Cryptosporidium in humans.Methodology/principal findingsA systematic search was conducted to obtain epidemiological papers of human Cryptosporidium infection/cryptosporidiosis from PubMed and Chinese databases. Finally, 164 papers were included in our analysis. At least 200,054 people from 27 provinces were involved in investigational studies of Cryptosporidium, with an average prevalence of 2.97%. The prevalence changed slightly over time. Variable prevalences were observed: 0.65-11.15% by province, 1.89-47.79% by population, 1.77-12.87% and 0-3.70% in rural and urban areas, respectively. The prevalence peak occurred in summer or autumn. Indirect person-to-person transmission was documented in one outbreak of cryptosporidiosis in a pediatric hospital. 263 Cryptosporidium isolates were obtained, and seven Cryptosporidium species were identified: C. hominis (48.3%), C. andersoni (22.43%), C. parvum (16.7%), C. meleagridis (8.36%), C. felis (3.04%), C. canis (0.76%) and C. suis (0.38%).Conclusions/significancesThis systematic review reflects current epidemiological status and characteristics of Cryptosporidium in humans in China. These data will be helpful to develop efficient control strategies to intervene with and prevent occurrence of human Cryptosporidium infection/cryptosporidiosis in China as well as have a reference effect to other countries. Further studies should focus on addressing a high frequency of C. andersoni in humans and a new challenge with respect to cryptosporidiosis with an increasing population of elderly people and patients with immunosuppressive diseases

Prevalence and genetic characterizations of Cryptosporidium spp. in pre-weaned and post-weaned piglets in Heilongjiang Province, China.

BACKGROUND: Cryptosporidium spp. are common intestinal protozoa of humans and animals. There have been few studies conducted on the molecular characterizations of pig-derived Cryptosporidium isolates worldwide, especially in China. Thus, the aim of the present study was to understand the prevalence, distribution and genotypes of Cryptosporidium in pigs in Heilongjiang Province, China. METHODOLOGY/PRINCIPAL FINDINGS: A total of 568 fecal samples from pre-weaned and post-weaned piglets were collected from eight pig farms from four areas of Heilongjiang Province. The average infection rate of Cryptosporidium was 1.6% (9/568) by microscopy. 113 samples were subjected to PCR amplification of the small subunit (SSU) rRNA gene of Cryptosporidium, with 55.8% (63/113) being positive for Cryptosporidium. Cryptosporidium suis (n = 31) and C. scrofarumn (n = 32) were identified by DNA sequencing of the SSU rRNA gene. Three types of C. scrofarumn were found at the SSU rRNA locus, with one novel type being detected. Using species/genotype-specific primers for pig-adapted Cryptosporidium spp., 22 and 23 respectively belonged to C. suis and C. scrofarum mono-infections, with 18 co-infections detected. The infection peaks for C. suis (60%, 24/40) and C. scrofarum (51.2%, 21/41) were respectively found in the piglets of 5 to 8 weeks and more than 8 weeks. CONCLUSION/SIGNIFICANCE: The detection of C. suis and C. scrofarum in pre-weaned and post-weaned piglets has public health implications, due to the fact that the two species are both zoonotic Cryptosporidium. The novel C. scrofarum type detected may be endemic to China

MLST subtypes and population genetic structure of Cryptosporidium andersoni from dairy cattle and beef cattle in northeastern China's Heilongjiang Province.

Cattle are the main reservoir host of C. andersoni, which shows a predominance in yearlings and adults of cattle. To understand the subtypes of C. andersoni and the population genetic structure in Heilongjiang Province, fecal specimens were collected from 420 dairy cattle and 405 beef cattle at the age of 12-14 months in eight cattle farms in five areas within this province and were screened for the presence of Cryptosporidium oocysts by microscopy after Sheather's sugar flotation technique. The average prevalence of Cryptosporidium spp. was 19.15% (158/825) and all the Cryptosporidium isolates were identified as C. andersoni by the SSU rRNA gene nested PCR-RFLP using SspI, VspI and MboII restriction enzymes. A total of 50 C. andersoni isolates were randomly selected and sequenced to confirm the RFLP results before they were subtyped by multilocus sequence typing (MLST) at the four microsatellite/minisatellite loci (MS1, MS2, MS3 and MS16). Four, one, two and one haplotypes were obtained at the four loci, respectively. The MLST subtype A4,A4,A4,A1 showed an absolute predominance and a wide distribution among the six MLST subtypes obtained in the investigated areas. Linkage disequilibrium analysis showed the presence of a clonal population genetic structure of C. andersoni in cattle, suggesting the absence of recombination among lineages. The finding of a clonal population genetic structure indicated that the prevalence of C. andersoni in cattle in Heilongjiang Province is not attributed to the introduction of cattle. Thus, prevention and control strategies should be focused on making stricter measures to avoid the occurrence of cross-transmission and re-infection between cattle individuals. These molecular data will also be helpful to explore the source attribution of infection/contamination of C. andersoni and to elucidate its transmission dynamics in Heilongjiang Province, even in China