Observation of an a_{0}-like State with Mass of 1.817 GeV in the Study of D_{s}^{+}→K_{S}^{0}K^{+}π^{0} Decays

Using e^{+}e^{-} annihilation data corresponding to an integrated luminosity of 6.32  fb^{-1} collected at center-of-mass energies between 4.178 and 4.226 GeV with the BESIII detector, we perform the first amplitude analysis of the decay D_{s}^{+}→K_{S}^{0}K^{+}π^{0} and determine the relative branching fractions and phases for intermediate processes. We observe an a_{0}-like state with mass of 1.817 GeV in its decay to K_{S}^{0}K^{+} for the first time. In addition, we measure the ratio {B[D_{s}^{+}→K[over ¯]^{*}(892)^{0}K^{+}]/B[D_{s}^{+}→K[over ¯]^{0}K^{*}(892)^{+}]} to be 2.35_{-0.23stat}^{+0.42}±0.10_{syst}. Finally, we provide a precision measurement of the absolute branching fraction B(D_{s}^{+}→K_{S}^{0}K^{+}π^{0})=(1.46±0.06_{stat}±0.05_{syst})%.

[Analysis of early severe postoperative complications and risk factors in 4255 patients who underwent bariatric and metabolic surgery in a single cente]

Objective: To analyze the incidence of early severe complications following bariatric and metabolic surgery and the experience of their diagnosis, treatment, and risk factors. Methods: In this retrospective observational study, the clinical data of 4255 patients who underwent bariatric and metabolic surgery between May 2010 and May 2022 in the Department of Bariatric and Metabolic Surgery of the First Affiliated Hospital of Nanjing Medical University were retrospectively collected. Among these patients, 1125 were male and 3130 were female. The mean age and body mass index (BMI) of the patients at the time of operation were 31.3±4.5 years and 36.5±6.4 kg/m², respectively. Regarding surgical type, 2397 patients underwent sleeve gastrectomy (SG), 489 underwent Roux-en-Y gastric bypass (RYGB), 1028 underwent sleeve gastrectomy plus jejunojejunal bypass (SG+JJB), and 341 underwent single anastomosis duodenal switch (SADS). The inclusion criteria were patients (1) with a Clavien-Dindo grade of ≥III; (2) who were undergoing SG, RYGB, SG-JJB, or SADS; and (3) who had complete clinical data. The exclusion criteria were patients (1) undergoing revisional surgery and (2) other operations during the bariatric and metabolic surgery. The Clavien-Dindo classification was used to analyze the incidence of early severe postoperative complications and their prognosis. Early severe postoperative complications were defined as Clavien-Dindo ≥ III complications within 30 days after surgery. Meanwhile, multivariate logistic regression model was used to identify risk factors of the complications. Results: Summary of early severe complications following bariatric and metabolic surgery: (1) of the 4255 patients, 22 (12 male and 10 female) exhibited early severe complications (0.52%). The mean age and BMI of these patients were 41.1±9.9 years and 36.9±8.2 kg/m², respectively. Preoperatively, 7 patients had hypertension, 10 had type 2 diabetes mellitus, 1 had respiratory failure, and 1 had heart failure. The severe complications included 9 patients (0.21%) with grade IIIa, 11 (0.26%) with grade IIIb, 1 (0.02%) with grade IVa, and 1 (0.02%) with grade V complications. The incidences of severe postoperative complications in the different surgical procedures were 0.17% for SG (4/2397), 0.61% for RYGB (3/489), 0.58% for SG+JJB (6/1028), and 2.64% for SADS (9/341). The common severe complications were leakage (0.28%, 12 patients), bleeding (0.14%, 6 patients), and obstruction (0.05%, 2 patients). (2) Management of complications: Grade IIIa complications (including eight patients with leakage and one with severe inflammation) were treated with antibiotics, nasogastric and nutritional tube placements, and CT-guided drainage. For grade IIIa complications, five patients with bleeding were treated with reoperation, and all the patients recovered; four patients with leakage were treated with reoperation, wherein three were converted to RYGB and one patient underwent resuturing of the leakage site; two patients with obstruction were treated with adhesiolysis. The patient with grade IVa complication (including respiratory failure complicated with acid aspiration) was treated in the ICU. For the grade V complication, bleeding in a patient with SG+JJB was treated with reoperation, which confirmed the bleeding of short gastric vessels. Unfortunately, the patient died. (3) Risk factor analysis of early severe complications: univariate analysis detected that sex, age, type 2 diabetes mellitus, operation time, and surgical type were associated with postoperative complications (P<0.05). However, multivariate analysis indicated that an age of ≥31.3 years (odds ratio [OR] = 5.423, 95% confidence interval [CI]: 1.004-29.278, P=0.049) and surgical type (SADS: OR = 19.758, 95%CI: 5.803-67.282, P<0.001; RYGB: OR = 9.752, 95%CI: 2.456-38.723, P=0.001; SG+JJB: OR = 5.706, 95%CI: 1.966- 16.559, P=0.001) were independent risk factors of early severe complications following bariatric and metabolic surgery. Conclusion: Bariatric and metabolic surgery is safe. Its common postoperative complications include leakage, bleeding, and obstruction, which require early detection, diagnosis, and treatment to improve treatment outcomes. Age and surgical type are independent risk factors of early severe complications following bariatric and metabolic surgery.

[Current status of sleeve gastrectomy plus jejunojejunal bypass]

At present, sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) have become the major bariatric and metabolic surgical procedures, but neither of them is perfect. Adding jejunojejunal bypass (JJB) to SG can enhance weight loss and hypoglycemic effect. Present clinical results show that the short-term weight loss effect of SG-JJB is better than SG, and the weight loss and hypoglycemic effect is similar to RYGB. However, SG-JJB does not have various complications like traditional jejunal ileal bypass (JIB). The existing evidence shows that SG-JJB is a safe and effective bariatric and metabolic surgery, with relatively simple technical requirement. Meanwhile, SG-JJB has almost no dumping syndrome or ulcers, and facilitates endoscopic examination of the biliary tract, and has no blind gastric pouch. Thus, SG-JJB has some clinical application prospects, but further high-quality research with long-term follow-up is needed.

Precise Measurements of Decay Parameters and CP Asymmetry with Entangled Λ-Λ[over ¯] Pairs

Based on 10 billion J/ψ events collected at the BESIII experiment, a search for CP violation in Λ decay is performed in the difference between CP-odd decay parameters α_{-} for Λ→pπ^{-} and α_{+} for Λ[over ¯]→p[over ¯]π^{+} by using the process e^{+}e^{-}→J/ψ→ΛΛ[over ¯]. With a five-dimensional fit to the full angular distributions of the daughter baryon, the most precise values for the decay parameters are determined to be α_{-}=0.7519±0.0036±0.0024 and α_{+}=-0.7559±0.0036±0.0030, respectively. The Λ and Λ[over ¯] averaged value of the decay parameter is extracted to be α_{avg}=0.7542±0.0010±0.0024 with unprecedented accuracy. The CP asymmetry A_{CP}=(α_{-}+α_{+})/(α_{-}-α_{+}) is determined to be -0.0025±0.0046±0.0012, which is one of the most precise measurements in the baryon sector. The reported results for the decay parameter will play an important role in the studies of the polarizations and CP violations for the strange, charmed and beauty baryons.

First Observation of the Direct Production of the χ_{c1} in e^{+}e^{-} Annihilation

We study the direct production of the J^{PC}=1^{++} charmonium state χ_{c1}(1P) in electron-positron annihilation by carrying out an energy scan around the mass of the χ_{c1}(1P). The data were collected with the BESIII detector at the BEPCII collider. An interference pattern between the signal process e^{+}e^{-}→χ_{c1}(1P)→γJ/ψ→γμ^{+}μ^{-} and the background processes e^{+}e^{-}→γ_{ISR}J/ψ→γ_{ISR}μ^{+}μ^{-} and e^{+}e^{-}→γ_{ISR}μ^{+}μ^{-} is observed by combining all the data samples. The χ_{c1}(1P) signal is observed with a significance of 5.1σ. This is the first observation of a C-even state directly produced in e^{+}e^{-} annihilation. The electronic width of the χ_{c1}(1P) resonance is determined to be Γ_{ee}=(0.12_{-0.08}^{+0.13})  eV, which is of the same order of magnitude as theoretical calculations.

Evidence for a Neutral Near-Threshold Structure in the K_{S}^{0} Recoil-Mass Spectra in e^{+}e^{-}→K_{S}^{0}D_{s}^{+}D^{*-} and e^{+}e^{-}→K_{S}^{0}D_{s}^{*+}D^{-}

We study the processes e^{+}e^{-}→K_{S}^{0}D_{s}^{+}D^{*-} and e^{+}e^{-}→K_{S}^{0}D_{s}^{*+}D^{-}, as well as their charge conjugated processes, at five center-of-mass energies between 4.628 and 4.699 GeV, using data samples corresponding to an integrated luminosity of 3.8  fb^{-1} collected by the BESIII detector at the BEPCII storage ring. Based on a partial reconstruction technique, we find evidence of a structure near the thresholds for D_{s}^{+}D^{*-} and D_{s}^{*+}D^{-} production in the K_{S}^{0} recoil-mass spectrum, which we refer to as the Z_{cs}(3985)^{0}. Fitting with a Breit-Wigner line shape, we find the mass of the structure to be (3992.2±1.7±1.6)  MeV/c^{2} and the width to be (7.7_{-3.8}^{+4.1}±4.3)  MeV, where the first uncertainties are statistical and the second are systematic. The significance of the Z_{cs}(3985)^{0} signal is found to be 4.6σ including both the statistical and systematic uncertainty. We report the Born cross section multiplied by the branching fraction at different energy points. The mass of the Z_{cs}(3985)^{0} is close to that of the Z_{cs}(3985)^{+}. Assuming SU(3) symmetry, the cross section of the neutral channel is consistent with that of the charged one. Hence, we conclude that the Z_{cs}(3985)^{0} is the isospin partner of the Z_{cs}(3985)^{+}.

Observation of Resonance Structures in e^{+}e^{-}→π^{+}π^{-}ψ_{2}(3823) and Mass Measurement of ψ_{2}(3823)

Using a data sample corresponding to an integrated luminosity of 11.3  fb^{-1} collected at center-of-mass energies from 4.23 to 4.70 GeV with the BESIII detector, we measure the product of the e^{+}e^{-}→π^{+}π^{-}ψ_{2}(3823) cross section and the branching fraction B[ψ_{2}(3823)→γχ_{c1}]. For the first time, resonance structure is observed in the cross section line shape of e^{+}e^{-}→π^{+}π^{-}ψ_{2}(3823) with significances exceeding 5σ. A fit to data with two coherent Breit-Wigner resonances modeling the sqrt[s]-dependent cross section yields M(R_{1})=4406.9±17.2±4.5  MeV/c^{2}, Γ(R_{1})=128.1±37.2±2.3  MeV, and M(R_{2})=4647.9±8.6±0.8  MeV/c^{2}, Γ(R_{2})=33.1±18.6±4.1  MeV. Though weakly disfavored by the data, a single resonance with M(R)=4417.5±26.2±3.5  MeV/c^{2}, Γ(R)=245±48±13  MeV is also possible to interpret data. This observation deepens our understanding of the nature of the vector charmoniumlike states. The mass of the ψ_{2}(3823) state is measured as (3823.12±0.43±0.13)  MeV/c^{2}, which is the most precise measurement to date.

First Measurement of High-Energy Reactor Antineutrinos at Daya Bay

This Letter reports the first measurement of high-energy reactor antineutrinos at Daya Bay, with nearly 9000 inverse beta decay candidates in the prompt energy region of 8-12 MeV observed over 1958 days of data collection. A multivariate analysis is used to separate 2500 signal events from background statistically. The hypothesis of no reactor antineutrinos with neutrino energy above 10 MeV is rejected with a significance of 6.2 standard deviations. A 29% antineutrino flux deficit in the prompt energy region of 8-11 MeV is observed compared to a recent model prediction. We provide the unfolded antineutrino spectrum above 7 MeV as a data-based reference for other experiments. This result provides the first direct observation of the production of antineutrinos from several high-Q_{β} isotopes in commercial reactors.

Observation of a State X(2600) in the π^{+}π^{-}η' System in the Process J/ψ→γπ^{+}π^{-}η'

Based on (10087±44)×10^{6}  J/ψ events collected with the BESIII detector, the process J/ψ→γπ^{+}π^{-}η^{'} is studied using two largest decay channels of the η^{'} meson, η^{'}→γπ^{+}π^{-} and η^{'}→ηπ^{+}π^{-}, η→γγ. A new resonance, which we denote as the X(2600), is observed with a statistical significance larger than 20σ in the π^{+}π^{-}η^{'} invariant mass spectrum, and it has a connection to a structure around 1.5  GeV/c^{2} in the π^{+}π^{-} invariant mass spectrum. A simultaneous fit on the π^{+}π^{-}η^{'} and π^{+}π^{-} invariant mass spectra with the two η^{'} decay modes indicates that the mass and width of the X(2600) state are 2618.3±2.0_{-1.4}^{+16.3}  MeV/c^{2} and 195±5_{-17}^{+26}  MeV, where the first uncertainties are statistical, and the second systematic.

Observation of J/ψ Electromagnetic Dalitz Decays to X(1835), X(2120), and X(2370)

Using a sample of about 10^{10}  J/ψ events collected at a center-of-mass energy sqrt[s]=3.097  GeV with the BESIII detector, the electromagnetic Dalitz decays J/ψ→e^{+}e^{-}π^{+}π^{-}η^{'}, with η^{'}→γπ^{+}π^{-} and η^{'}→π^{+}π^{-}η, have been studied. The decay J/ψ→e^{+}e^{-}X(1835) is observed with a significance of 15σ, and also an e^{+}e^{-} invariant-mass dependent transition form factor of J/ψ→e^{+}e^{-}X(1835) is presented for the first time. The intermediate states X(2120) and X(2370) are also observed in the π^{+}π^{-}η^{'} invariant-mass spectrum with significances of 5.3σ and 7.3σ. The corresponding product branching fractions for J/ψ→e^{+}e^{-}X, X→π^{+}π^{-}η^{'} [X=X(1835), X(2120), and X(2370)] are reported.

Probing CP symmetry and weak phases with entangled double-strange baryons

Though immensely successful, the standard model of particle physics does not offer any explanation as to why our Universe contains so much more matter than antimatter. A key to a dynamically generated matter-antimatter asymmetry is the existence of processes that violate the combined charge conjugation and parity (CP) symmetry1. As such, precision tests of CP symmetry may be used to search for physics beyond the standard model. However, hadrons decay through an interplay of strong and weak processes, quantified in terms of relative phases between the amplitudes. Although previous experiments constructed CP observables that depend on both strong and weak phases, we present an approach where sequential two-body decays of entangled multi-strange baryon-antibaryon pairs provide a separation between these phases. Our method, exploiting spin entanglement between the double-strange Ξ- baryon and its antiparticle2 [Formula: see text], has enabled a direct determination of the weak-phase difference, (ξP - ξS) = (1.2 ± 3.4 ± 0.8) × 10-2 rad. Furthermore, three independent CP observables can be constructed from our measured parameters. The precision in the estimated parameters for a given data sample size is several orders of magnitude greater than achieved with previous methods3. Finally, we provide an independent measurement of the recently debated Λ decay parameter αΛ (refs. 4,5). The [Formula: see text] asymmetry is in agreement with and compatible in precision to the most precise previous measurement4.

[Extent of lymphadenectomy for local advanced gastric cancer in the era of perioperative treatment and minimally invasive surgery]

The standard lymphadenectomy (D2) is the most important quality control index for the surgical treatment of locally advanced gastric cancer (LAGC). It is debatable whether there is a survival benefit of extended lymphadenectomy beyond D2 dissection. Para-aortic lymph nodes are not included in the range of D2 lymph node dissection. However, the patients with para-aortic node metastasis can get better survival after neoadjuvant chemotherapy and D2+ surgery. Lymph nodes along the superior mesenteric vein (No.14v) are considered as regional nodes, and the prognosis of patients with No.14v metastasis treated with D2+ lymph node dissection is significantly better than that of stage Ⅳ patients undergoing only D2 dissection. No.14v was not included in the D2 lymph node dissection paradigm. In case with nodal metastases in No.6 group, D2+ dissection is recommended. Lymph nodes at the splenic hilum (No.10) are not included in the range of D2 dissection, when the tumor infiltrates the greater curvature of the stomach, D2+ splenectomy or No.10 nodal dissection should be performed. Lymph nodes on the posterior surface of pancreatic head (No.13) do not belong to the D2 range, but the rate of metastasis is significantly higher when distal gastric cancer invades the duodenum, D2+ lymphadenectomy is recommended. Lymph node dissection in the posterior group of the common hepatic artery (No.8p) can improve the patient's long-term survival, but there is no support from of evidence-based medicine. In the era of perioperative treatment and minimally invasive surgery in China, open or laparoscopic D2 lymphadenectomy is recommended for cT3-4N1M0 patients and SOX neoadjuvant chemotherapy plus D2 surgery plus SOX adjuvant chemotherapy should be carried out for patients with cT3-4N2-4M0. Depending on the patient's condition and the experience of the surgical team, open or laparoscopic surgery can be performed.

Observation of the Singly Cabibbo Suppressed Decay Λ_{c}^{+}→nπ^{+}

The singly Cabibbo-suppressed decay Λ_{c}^{+}→nπ^{+} is observed for the first time with a statistical significance of 7.3σ by using 3.9  fb^{-1} of e^{+}e^{-} collision data collected at center-of-mass energies between 4.612 and 4.699 GeV with the BESIII detector at BEPCII. The branching fraction of Λ_{c}^{+}→nπ^{+} is measured to be (6.6±1.2_{stat}±0.4_{syst})×10^{-4}. By taking the upper limit of branching fractions of Λ_{c}^{+}→pπ^{0} from the Belle experiment, the ratio of branching fractions between Λ_{c}^{+}→nπ^{+} and Λ_{c}^{+}→pπ^{0} is calculated to be larger than 7.2 at the 90% confidence level, which disagrees with most predictions of the available phenomenological models. In addition, the branching fractions of the Cabibbo-favored decays Λ_{c}^{+}→Λπ^{+} and Λ_{c}^{+}→Σ^{0}π^{+} are measured to be (1.31±0.08_{stat}±0.05_{syst})×10^{-2} and (1.22±0.08_{stat}±0.07_{syst})×10^{-2}, respectively, which are consistent with previous results.

A microbiome study reveals the potential relationship between the bacterial diversity of a gymnastics hall and human health

Currently, investigations on the microbiota of sports centers and related facilities have been carried out in some countries, which showed that Microsporum gypseum, Trichophyton mentagrophytes and T. tonsurans are important dermatoprotofungi. In China, some research on athletes and sports equipment between the fungal community and public health has made some interesting achievements. However, the bacterial group among them has not been reported. Therefore, The aim of this study was to uncover (I) gymnastic equipment is there potential pathogenic factors and (ii) is there any difference in the biomarker of bacterial in different types of gymnastic room? The samples were collected from the gymnastics halls of one university in western China and main sports equipment, including gymnastics carpets, moving barres, hoops and balls, as well as wall bars, parallel bars and horizontal bars. The 16S rDNA of all the samples was sequenced, and the analyses were performed using FaproTax, Bug base function prediction and Line Discriminant Analysis (LDA) Effect Size. A 16S rDNA sequence analysis revealed abundant bacterial species biodiversity on gymnasts and apparatuses from two gymnastics halls at a university in western China. An analysis using the FaproTax and Bugbase functional prediction platforms showed that there were some opportunistic pathogens on the athletes and equipment from the Rhythmic Gymnastics (RG) and Artistic Gymnastics (AG) halls, such as Staphylococcus and Corynebacteiaceae. Infectious agents associated with cancer induction and development, such as Ruminococcaceae, Veillonellaceae and Moraxellaceae, as well as microbial toxin producers with a potential impact on human health, were also detected. According to a line discriminant analysis (LDA effect size), the bacterial biomarker groups of the two gymnasiums were different at the phylum-genus level: for RG, Erysipelatoclostridium, Lachnospiraceae and Bacteroidales, while for AG, Rhizobiales. Based on the results of the investigation, we suggest that more comprehensive consideration should be given to indoor microbial biodiversity and related public health problems in school gymnasiums.

Short-Range Structural Connections Are More Severely Damaged in Early-Stage MS

BACKGROUND AND PURPOSE

Long-range connections are more severely damaged and relevant for cognition in long-standing MS. However, the evolution of such coordinated network damage in patients with MS is unclear. We investigated whether short- and long-range structural connections sustained equal damage in early-stage MS.

MATERIALS AND METHODS

Sixteen patients with early-stage MS and 17 healthy controls were scanned by high-resolution, multishell diffusion imaging on 7T MR imaging and assessed cognitively. We investigated macrostructural properties in short- and long-range fibers and of microstructural metrics derived from 2 quantitative diffusion MR imaging models: DTI and neurite orientation dispersion and density imaging.

RESULTS

Patients had significant WM integrity damage-that is, higher radial diffusivity and a lower intracellular volume fraction in the focal WM lesions. Compared with the healthy controls, the patients had noticeable microstructure changes in both short- and long-range fibers, including increased radial diffusivity, mean diffusivity, and axial diffusivity. Z scores further indicated greater damage in the short-range fibers than in the long-range fibers.

CONCLUSIONS

Our findings demonstrate that more severe demyelination preceding axonal degeneration occurs in short-range connections but not in long-range connections in early-stage MS, suggesting the possibility that there are cortical lesions that are undetectable by current MR imaging.

Joint Determination of Reactor Antineutrino Spectra from ^{235}U and ^{239}Pu Fission by Daya Bay and PROSPECT

A joint determination of the reactor antineutrino spectra resulting from the fission of ^{235}U and ^{239}Pu has been carried out by the Daya Bay and PROSPECT Collaborations. This Letter reports the level of consistency of ^{235}U spectrum measurements from the two experiments and presents new results from a joint analysis of both data sets. The measurements are found to be consistent. The combined analysis reduces the degeneracy between the dominant ^{235}U and ^{239}Pu isotopes and improves the uncertainty of the ^{235}U spectral shape to about 3%. The ^{235}U and ^{239}Pu antineutrino energy spectra are unfolded from the jointly deconvolved reactor spectra using the Wiener-SVD unfolding method, providing a data-based reference for other reactor antineutrino experiments and other applications. This is the first measurement of the ^{235}U and ^{239}Pu spectra based on the combination of experiments at low- and highly enriched uranium reactors.

Measurement of the Cross Section for e^{+}e^{-}→Hadrons at Energies from 2.2324 to 3.6710 GeV

Based on electron-positron collision data collected with the BESIII detector operating at the Beijing Electron-Positron Collider II storage rings, the value of R≡σ(e^{+}e^{-}→hadrons)/σ(e^{+}e^{-}→μ^{+}μ^{-}) is measured at 14 center-of-mass energies from 2.2324 to 3.6710 GeV. The resulting uncertainties are less than 3.0% and are dominated by systematic uncertainties.

Scattering of surface waves by a vertical truncated structured cylinder

This paper describes the solution to the problem of scattering of plane incident waves on water of constant depth by a bottom mounted circular cylinder, extending partially through the depth, which has an internal structure comprised of closely spaced thin vertical barriers between which fluid is allowed to flow. The problem is solved under full depth-dependent linearized water wave theory using an effective medium equation to describe the fluid motion in cylinder and effective boundary conditions to match that flow to the fluid region outside the cylinder. The interest in this problem lies in the development of novel solution methods for fully three-dimensional water wave interaction with bathymetric plate arrays. Results computed using this theory are compared with a shallow water approximation based on the recent work of Marangos & Porter (2021 Shallow water theory for structured bathymetry. Proc. R. Soc. A477, 20210421.) and with accurate computations of an exact representation of the geometry using a discrete set of plates. Other results highlight the resonant directional lensing effects of this type of cylindrical plate array device.

[Effect factors of collateral blood supply of patients with early trimester cesarean scar pregnancy]

Objective: To investigate the characteristics and effect factors of collateral blood supply of patients with early trimester cesarean scar pregnancy(CSP). Methods: This study was a multicenter case-control study, with 219 inpatients with CSP in First People's Hospital of Zhengzhou, Zhengzhou Central Hospital, Third People's Hospital of Zhengzhou and Henan No3 Provincial People's Hospital from January 1, 2017 to June 30, 2020 who were selected to obtain their clinical data. Double-blind method was performed in digital subtraction angiography imaging analysis. The patients were divided into collateral blood supply group and non-collateral blood supply group, and the incidence of collateral blood supply of patients with early trimester CSP was calculated. Multivariate binary logistic regression analysis was performed to find the independent risk factors of collateral blood supply of patients with early trimester CSP. As well, clinical outcomes after uterine artery embolization (UAE) were compared between the two groups. Results: A total of 219 patients with early trimester CSP have average age of (32.4±5.0) years old and average pregnancy of (51.0±10.6) days. The incidence of collateral blood supply was 12.3% (27 cases), of which16 cases were on the left, 6 on the right and 5 in both sides. A total of 43 collateral vessels were found, with 1.59 vessels per patient on average. Bladder artery was the most common source of collateral blood supply, accounting for 74.4% (32/43), followed by internal pudendal artery for 18.6% (8/43). Multivariate binary logistic regression analysis showed that gestational weeks ≥8 weeks, maximum diameter of gestational sac ≥50 mm and rich blood supply of gestational sac are independent risk factors for collateral blood supply of patients with early trimester CSP, with OR (95%CI) 3.68 (1.06-12.76), 7.00 (1.52-32.19)、9.96 (3.59-27.58), respectively, all P<0.05. The success rates of UAE were 100% in both groups. The reduction in serum β-Human chorionic gonadotropin (β-HCG) level at 24 hours after UAE, vaginal bleeding during uterine curettage, hysterectomy and menstrual recovery time were not found to have significant difference between groups (all P>0.05). Conclusions: Early trimester CSP leads to a certain occurrence of collateral blood supply, which may have adverse impact on the efficacy of UAE and patient safety. Gestational weeks, the maximum diameter of gestational sac and the degree of vascularization of gestation sac have certain value in suggesting the collateral blood supply of patients with early trimester CSP, which is helpful for the complete embolization of gestational sac in the process of UAE.

First Measurement of Polarizations in the Decay D^{0}→ωφ

Using a data sample corresponding to an integrated luminosity of 2.93  fb^{-1} collected at a center-of-mass energy sqrt[s]=3.773  GeV by the BESIII detector, the decay D^{0}→ωϕ is observed for the first time. The branching fraction is measured to be (6.48±0.96±0.40)×10^{-4} with a significance of 6.3σ, where the first and second uncertainties are statistical and systematic, respectively. An angular analysis reveals that the ϕ and ω mesons from the D^{0}→ωϕ decay are transversely polarized. The 95% confidence level upper limit on longitudinal polarization fraction is set to be less than 0.24, which is inconsistent with current theoretical expectations and challenges our understanding of the underlying dynamics in charm meson decays.