Seasonal Risk Assessment of Water-Electricity Nexus Systems under Water Consumption Policy Constraint

Previous studies have estimated power plant cooling water consumption based on the long-term average cooling water consumption intensity (WI: water consumption per unit of electricity generation) at an annual scale. However, the impacts of the seasonality of WI and streamflow on electricity generation are less well understood. In this study, a risk assessment method is developed to explore the seasonal risk of water-electricity nexus based on the Integrated Environmental Control Model, which can simulate variable WIs in response to daily weather conditions and avoid underestimation in WIs as well as nexus risk during dry seasons. Three indicators, reliability, maximum time to recovery, and total power generation loss, are proposed to quantify the seasonal nexus risk under water consumption policy constraint represented by the allowed maximum percentage of water consumption to streamflow. The applications of the method in two representative watersheds demonstrate that the nexus risk is highly seasonal and is greatly impacted by the seasonal variability of streamflow rather than annual average water resources conditions on which most previous studies are based. The nexus is found more risky in the watershed with almost double mean annual streamflow and greater streamflow variability, compared with the watershed with less streamflow variability.

Observation of a Resonant Structure in e^{+}e^{-}→K^{+}K^{-}π^{0}π^{0}

A partial-wave analysis is performed for the process e^{+}e^{-}→K^{+}K^{-}π^{0}π^{0} at the center-of-mass energies ranging from 2.000 to 2.644 GeV. The data samples of e^{+}e^{-} collisions, collected by the BESIII detector at the BEPCII collider with a total integrated luminosity of 300  pb^{-1}, are analyzed. The total Born cross sections for the process e^{+}e^{-}→K^{+}K^{-}π^{0}π^{0}, as well as the Born cross sections for the subprocesses e^{+}e^{-}→ϕπ^{0}π^{0}, K^{+}(1460)K^{-}, K_{1}^{+}(1400)K^{-}, K_{1}^{+}(1270)K^{-}, and K^{*+}(892)K^{*-}(892), are measured versus the center-of-mass energy. The corresponding results for e^{+}e^{-}→K^{+}K^{-}π^{0}π^{0} and ϕπ^{0}π^{0} are consistent with those of BABAR with better precision. By analyzing the cross sections for the four subprocesses, K^{+}(1460)K^{-}, K_{1}^{+}(1400)K^{-}, K_{1}^{+}(1270)K^{-}, and K^{*+}(892)K^{*-}(892), a structure with mass M=(2126.5±16.8±12.4)  MeV/c^{2} and width Γ=(106.9±32.1±28.1)  MeV is observed with an overall statistical significance of 6.3σ, although with very limited significance in the subprocesses e^{+}e^{-}→K_{1}^{+}(1270)K^{-} and K^{*+}(892)K^{*-}(892). The resonant parameters of the observed structure suggest it can be identified with the ϕ(2170), thus the results provide valuable input to the internal nature of the ϕ(2170).

Factors associated with resistance to complications in long-standing type 1 diabetes in China

OBJECTIVE

Type 1 diabetes (T1DM) is associated with a higher risk of premature death, but there are factors in certain patients with T1DM that protect them from complications and premature death. These factors had not been identified in non-Caucasian populations, so we aimed to identify factors that protect against the development of diabetic nephropathy (DN) and diabetic retinopathy (DR) in long-standing T1DM in China

METHODS

Ninety-five T1DM patients with >30 years’ duration of diabetes were enrolled in this nationwide study. Differences between groups of patients with and without complications were compared, and multivariable regression analysis was used to evaluate the relationships between candidate protective factors and the development of DN or DR.

RESULTS

Thirty of the participants did not have DN and the same amount did not have DR. 6/52 of participants without DN were from a rural area, whereas 11/28 of participants with DN had been born in a rural area (P = 0.005). Systolic blood pressure (SBP) was higher in participants with DN (135 ± 26 mmHg vs 121 ± 13 mmHg; P = 0.002). In participants without DR, 27/30 were married or cohabitating, and only 3/30 were single, never married, or widowed, but for those with proliferative DR (PDR), 13/26 had been married (P = 0.003). A rural or urban origin and SBP were associated with DN in the multivariable analysis.

CONCLUSION

we have shown that higher socioeconomic status, indicated by birth in an urban area, and being married or cohabitating, are accompanied by better blood pressure control and a lower risk of microvascular complications in Chinese patients with long-standing T1DM. These findings illustrate the importance of improving care for patients with T1DM in China.

Two-dimensional grating coupler on silicon with a high coupling efficiency and a low polarization-dependent loss

Two-dimensional grating couplers are important components for silicon photonic circuits to achieve light coupling from/to a fiber for both polarizations. A two-dimensional grating coupler structure with a high coupling efficiency and a low polarization dependent loss is demonstrated. Using two crossing ellipses as the grating scatter and a diamond-like grating lattice, the polarization dependent loss of the grating coupler can be reduced. The coupling loss is further decreased with a metal mirror, which reaches -1.73 dB theoretically at 1310 nm wavelength. Experimentally, -2.37 dB coupling loss is achieved with an 1 dB coupling bandwidth of 29 nm. The corresponding PDL was measured lower than 0.2 dB in a wavelength range of 78 nm. The proposed configuration for the metal mirror also facilitates a robust wafer-scale post-processing as well as an easy fiber alignment.

Measurement of Proton Electromagnetic Form Factors in e^{+}e^{-}→pp[over ¯] in the Energy Region 2.00-3.08 GeV

The process of e^{+}e^{-}→pp[over ¯] is studied at 22 center-of-mass energy points (sqrt[s]) from 2.00 to 3.08 GeV, exploiting 688.5  pb^{-1} of data collected with the BESIII detector operating at the BEPCII collider. The Born cross section (σ_{pp[over ¯]}) of e^{+}e^{-}→pp[over ¯] is measured with the energy-scan technique and it is found to be consistent with previously published data, but with much improved accuracy. In addition, the electromagnetic form-factor ratio (|G_{E}/G_{M}|) and the value of the effective (|G_{eff}|), electric (|G_{E}|), and magnetic (|G_{M}|) form factors are measured by studying the helicity angle of the proton at 16 center-of-mass energy points. |G_{E}/G_{M}| and |G_{M}| are determined with high accuracy, providing uncertainties comparable to data in the spacelike region, and |G_{E}| is measured for the first time. We reach unprecedented accuracy, and precision results in the timelike region provide information to improve our understanding of the proton inner structure and to test theoretical models which depend on nonperturbative quantum chromodynamics.

Measurement of the Cross Section for e^{+}e^{-}→Ξ^{-}Ξ[over ¯]^{+} and Observation of an Excited Ξ Baryon

Using a total of 11.0  fb^{-1} of e^{+}e^{-} collision data with center-of-mass energies between 4.009 and 4.6 GeV and collected with the BESIII detector at BEPCII, we measure fifteen exclusive cross sections and effective form factors for the process e^{+}e^{-}→Ξ^{-}Ξ[over ¯]^{+} by means of a single baryon-tag method. After performing a fit to the dressed cross section of e^{+}e^{-}→Ξ^{-}Ξ[over ¯]^{+}, no significant ψ(4230) or ψ(4260) resonance is observed in the Ξ^{-}Ξ[over ¯]^{+} final states, and upper limits at the 90% confidence level on Γ_{ee}B for the processes ψ(4230)/ψ(4260)→Ξ^{-}Ξ[over ¯]^{+} are determined. In addition, an excited Ξ baryon at 1820  MeV/c^{2} is observed with a statistical significance of 6.2-6.5σ by including the systematic uncertainty, and the mass and width are measured to be M=(1825.5±4.7±4.7)  MeV/c^{2} and Γ=(17.0±15.0±7.9)  MeV, which confirms the existence of the J^{P}=3/2^{-} state Ξ(1820).

[Analysis on monitoring results of occupational hazards in Yangzhou city from 2014 to 2018]

Objective: To undersand the monitor of occupational hazards in the enterprises in the past 5 years, as well as the distribution of occupational disease hazards and their dynamic changes in their respective jurisdictions, for providing scientific basis for prevention and control of occupational diseases in relevant departments. Methods: Taking the method of cluster sampling, select the monitoring results of the occupational disease hazard factors commissioned by the Municipal Center for Disease Control and Prevention from 2014 to 2018 and the annual monitoring data of the network of the occupational hazard declaration system of the Safety Supervision Bureau, using chi-square test, trend Statistical analysis was performed by chi-square test or Fisher exact probability method. Results: There were 461 testing companies in the past 5 years, with a total of 15, 186 monitoring points and 43428 samples. The pass rate was 94.32% (14324/15186) . The pass rate was increasing year by year from 2014 to 2017 (P<0.05) ; The pass rate of various occupational disease hazards surveillance were greater than 90% except the rate of physical factors. In 2014, the qualified rate of physical factors was the lowest, which was 86.99% (1558/1791) ; the production rate of different production scale enterprises in 2018 was higher than that of 2014. From 2014 to 2018, the number of inspection enterprises and the number of inspection points of the joint-stock economy and state-owned economic enterprises are both high, 58 (10091 points) and 71 (1830 points) respectively; The qualified rate of state-owned economy and collective economy monitoring is high, 98.36% (1800/1830) and 100% (74/74) respectively. It had reached more than 95%; The enterprises tested mainly from the economic development zone and Guangling, respectively accounting for 34.27% (158/461) and 33.84% (156/461) of the total number of enterprises. Which followed by the Hanjiang, accounting for 23.21% of the total number of enterprises (107/461) ; The monitoring enterprises were mainly distributed in the manufacturing and power industries, which accounted for 85.25% (393/461) and 6.07% (28/461) of the total number of enterprises, respectively. Conclusion: The monitoring rate of enterprises had been increasing year by year from 2014 to 2018. Noise was the main disease prevention and controlling factor in the area.In addition, micro-enterprises, individual economy and foreign-invested economy were the key targets for occupational health.

Observation of the Semileptonic D^{+} Decay into the K[over ¯]_{1}(1270)^{0} Axial-Vector Meson

By analyzing a 2.93  fb^{-1} data sample of e^{+}e^{-} collisions, recorded at a center-of-mass energy of 3.773 GeV with the BESIII detector operated at the BEPCII collider, we report the first observation of the semileptonic D^{+} transition into the axial-vector meson D^{+}→K[over ¯]_{1}(1270)^{0}e^{+}ν_{e} with a statistical significance greater than 10σ. Its decay branching fraction is determined to be B[D^{+}→K[over ¯]_{1}(1270)^{0}e^{+}ν_{e}]=(2.30±0.26_{-0.21}^{+0.18}±0.25)×10^{-3}, where the first and second uncertainties are statistical and systematic, respectively, and the third originates from the input branching fraction of K[over ¯]_{1}(1270)^{0}→K^{-}π^{+}π^{0}.

Observation of the Leptonic Decay D^{+}→τ^{+}ν_{τ}

We report the first observation of D^{+}→τ^{+}ν_{τ} with a significance of 5.1σ. We measure B(D^{+}→τ^{+}ν_{τ})=(1.20±0.24_{stat}±0.12_{syst})×10^{-3}. Taking the world average B(D^{+}→μ^{+}ν_{μ})=(3.74±0.17)×10^{-4}, we obtain R_{τ/μ}=Γ(D^{+}→τ^{+}ν_{τ})/Γ(D^{+}→μ^{+}ν_{μ})=3.21±0.64_{stat}±0.43_{syst}., which is consistent with the standard model expectation of lepton flavor universality. Using external inputs, our results give values for the D^{+} decay constant f_{D^{+}} and the Cabibbo-Kobayashi-Maskawa matrix element |V_{cd}| that are consistent with, but less precise than, other determinations.

Is water shortage risk decreased at the expense of deteriorating water quality in a large water supply reservoir?

Reservoir operations affect both the quantity and quality of stored and discharged water. Hedging rules (HRs) are commonly used in water supply reservoir operations to ration water delivery and decrease water shortage risk. However, the increased carryover storage with hedging may aggravate reservoir eutrophication through complex effects on hydrodynamic, temperature, light, nutrient, and sediment conditions. The influencing mechanisms are unclear and require further investigation. This study applies a mathematical modeling approach to comparing the effects of standard operation policy (SOP) and HR, discussing the processes and driving factors, and exploring the relationship between water shortage and water quality indicators. We simulate reservoir operation by SOP and optimize HR to generate water supply schedules, and run a quasi-3D water quality model to simulate reservoir hydrodynamic conditions, nutrient cycles, water-sediment exchanges, and algal dynamics under various water supply schedules. The Danjiangkou Reservoir, the water source for China's South-North Water Transfer Project, is used as a case study. The HR for this reservoir decreases its water shortage risk from 22% under SOP to 8%. Modeling results find that the HR increases sediment phosphorus (P) release by 285.3 tons (5.7%) annually as a consequence of extended reservoir submerged area and aggravated hypolimnetic hypoxia. Increased P release can support algal growth, but this effect is set off by the enhancement of light limiting effect caused by higher storages under HR, consequently decreasing the annual mean chlorophyll a concentration in the deep reservoir by 18%. The HR also improves the horizontal mixing of water by changing the hydraulic retention time and flow velocity field, which mitigates algal bloom risks in the surrounding shallow-water zones but deteriorates water quality of the release to downstream. The water quality analysis offers implications for reservoir managers to coordinate their efforts in mitigating risks of water shortage and water quality degradation.

Hyperpolarized relaxometry based nuclear T1 noise spectroscopy in diamond

The origins of spin lifetimes in quantum systems is a matter of importance in several areas of quantum information. Spectrally mapping spin relaxation processes provides insight into their origin and motivates methods to mitigate them. In this paper, we map nuclear relaxation in a prototypical system of [Formula: see text] nuclei in diamond coupled to Nitrogen Vacancy (NV) centers over a wide field range (1 mT-7 T). Nuclear hyperpolarization through optically pumped NV electrons allows signal measurement savings exceeding million-fold over conventional methods. Through a systematic study with varying substitutional electron (P1 center) and [Formula: see text] concentrations, we identify the operational relaxation channels for the nuclei at different fields as well as the dominant role played by [Formula: see text] coupling to the interacting P1 electronic spin bath. These results motivate quantum control techniques for dissipation engineering to boost spin lifetimes in diamond, with applications including engineered quantum memories and hyperpolarized [Formula: see text] imaging.

Complete Measurement of the Λ Electromagnetic Form Factors

The exclusive process e^{+}e^{-}→ΛΛ[over ¯], with Λ→pπ^{-} and Λ[over ¯]→p[over ¯]π^{+}, has been studied at sqrt[s]=2.396  GeV for measurement of the timelike Λ electric and magnetic form factors, G_{E} and G_{M}. A data sample, corresponding to an integrated luminosity of 66.9  pb^{-1}, was collected with the BESIII detector for this purpose. A multidimensional analysis with a complete decomposition of the spin structure of the reaction enables a determination of the modulus of the ratio R=|G_{E}/G_{M}| and, for the first time for any baryon, the relative phase ΔΦ=Φ_{E}-Φ_{M}. The resulting values are R=0.96±0.14(stat)±0.02(syst) and ΔΦ=37°±12°(stat)±6°(syst), respectively. These are obtained using the recently established and most precise value of the asymmetry parameter α_{Λ}=0.750±0.010 measured by BESIII. In addition, the cross section is measured with unprecedented precision to be σ=118.7±5.3(stat)±5.1(syst)  pb, which corresponds to an effective form factor of |G|=0.123±0.003(stat)±0.003(syst). The contribution from two-photon exchange is found to be negligible. Our result enables the first complete determination of baryon timelike electromagnetic form factors.

Amplitude Analysis of D_{s}^{+}→π^{+}π^{0}η and First Observation of the W-Annihilation Dominant Decays D_{s}^{+}→a_{0}(980)^{+}π^{0} and D_{s}^{+}→a_{0}(980)^{0}π^{+}

We present the first amplitude analysis of the decay D_{s}^{+}→π^{+}π^{0}η. We use an e^{+}e^{-} collision data sample corresponding to an integrated luminosity of 3.19  fb^{-1} collected with the BESIII detector at a center-of-mass energy of 4.178 GeV. We observe for the first time the W-annihilation dominant decays D_{s}^{+}→a_{0}(980)^{+}π^{0} and D_{s}^{+}→a_{0}(980)^{0}π^{+}. We measure the absolute branching fraction B(D_{s}^{+}→a_{0}(980)^{+(0)}π^{0^{(}+)},a_{0}(980)^{+(0)}→π^{+(0)}η)=(1.46±0.15_{stat}±0.23_{sys})%, which is larger than the branching fractions of other measured pure W-annihilation decays by at least one order of magnitude. In addition, we measure the branching fraction of D_{s}^{+}→π^{+}π^{0}η with significantly improved precision.

Revealing the water-energy-food nexus in the Upper Yellow River Basin through multi-objective optimization for reservoir system

Since the 21st century, the natural runoff from the headwater region of the Yellow River has generally been decreasing, resulting in a particularly prominent contradiction in utilization of water resources. In this study, key components were identified from the perspective of water-energy-food (WEF) nexus, and a WEF nexus model was established for the Upper Yellow River Basin (UYRB), taking into consideration the benefits of water supply to the middle and lower reaches of Yellow River, food growth in major food-producing areas in the UYRB and hydropower utilization of the UYR reservoir system. The Multi-start Solver of LINGO and the ε constraint method were used to carry out multi-objective optimization, revealing the trade-off between the WEF benefits. 1) The model computed the Pareto non-inferior set of solutions for the electricity generated by the UYR reservoir system and the degree to which the water demands of the main intake areas (Ningxia and Inner Mongolia irrigated areas, and Toudaoguai section) are satisfied, quantifying the improvement room for the overall benefits brought about by the jointly optimal operation of the WEF sectors. 2) The historical operation of Longyangxia Reservoir, a multi-year storage reservoir, was evaluated, the results of which show that the realization of the WEF benefits is determined by the proper operation of Longyangxia Reservoir. To guarantee the overall benefits in the long term, Longyangxia Reservoir should maintain a high water level. 3) The trade-offs between the WEF benefits under different boundary conditions were discussed, including various initial/final fore-bay water levels of Longyangxia Reservoir and inflows of various total water amounts from the headwater region of the UYRB. The research reveals the WEF nexus in the UYRB under different scenarios, and moreover, the formulated multi-objective optimization model is a good example that can be extended to other similar WEF nexus systems worldwide.

Umbilical arterial Doppler ultrasonography predicts late pregnancy outcomes in patients with lupus nephritis: a multicenter study from southern China

OBJECTIVES

To investigate the fetal adverse pregnancy outcomes (APOs) and the predictive value of umbilical arterial Doppler ultrasonography in the third trimester in pregnant women with lupus nephritis (LN).

METHODS

A retrospective cohort study enrolling 203 LN patients from 2007 to 2017 was performed. Ultrasonic parameters were recorded.

RESULTS

Fetal APOs occurred in 103 patients (103/203, 50.7%). Sixty-six pregnancies (66/203, 32.5%) ended with preterm births. The incidence rate of intrauterine growth restriction (IUGR) was 18.2% (37/203). Fetal distress was noted in 23 pregnancies (23/203, 11.3%). All the Doppler parameters elevated in patients with IUGR, fetal distress, and composite conditions. Resistance index (RI) indicated the highest risk of IUGR and composite APOs. The cutoff values were 0.66 and 0.67, respectively. Sensitivities were 51.4% and 33.7%, and specificities were 87.4% and 92.1%. Peak velocity of the umbilical arteries at end-systole (Vmax, abbreviated as S) to that at end-diastole (Vmin, abbreviated as D) (S/D) ratio was also a best predictor for IUGR, with the optimal cutoff value of 2.88. Sensitivity and specificity were comparable with RI. Pulsatility index (PI) over 0.84 was an ideal indicator for fetal distress with an optimal combination of sensitivity (89.5%) and specificity (51.6%).

CONCLUSIONS

Fetal complications were frequent in patients with LN. Umbilical arterial Doppler ultrasonography was a useful measure to predict late IUGR, fetal distress, and the composite APOs.

[Expression of SMARCA4(BRG1) and SMARCB1(INI1) in dedifferentiated and undifferentiated endometrial carcinomas and their correlations with clinicopathological features]

Objective: To investigate the expression of SMARCA4 (BRG1) and SMARCB1 (INI-1) protein in endometrial dedifferentiated carcinoma (DDC) and undifferentiated carcinoma (UDC), and their correlation with clinicopathologic features. Methods: Clinicopathological information was gathered for 26 cases of DDC and UDC and consulting hospitals from January, 2006 to December, 2018 in Fudan University Shanghai Cancer Center, including 10 cases of DDC and 16 cases of UDC. Morphologic features and diagnosis were reviewed by two pathologists. Immunohistochemistry for expression of BRG1 and INI1 protein was performed. The correlations with clinicopathologic features were analyzed. Results: BRG1 and INI1 loss were present in 14 of 26 cases of DDC/UDC, including 12 BRG1-deficient cases and 2 INI1-deficient cases, respectively. Six cases demonstrated variable amounts of rhabdoid cells in 14 BRG1/INI1-deficient cases, and only 1 case showed rhabdoid cells in the 12 intact expression cases. However, there was no significantly statistical difference (P=0.060). Age, invasive depth, lymph node status and FIGO stage were not associated with the expression of the BRG1 and INI1 (P=0.437, P=0.672, P=0.242, P=0.348). Remarkably, the BGR1/INI1-deficient patients had worse survival than those with intact expression (4.7 vs. 22.9, P=0.033). Conclusion: BRG1/INI1-deficient is observed in approximately half of DDC and UDC. Identification of these tumors is clinically relevant due to their more aggressive behavior and poor prognosis. Hence, BRG1 and INI1 immunohistochemical stains should be performed for DDC and UDC in order to help the pathologists to distinguish these tumors from other carcinomas, and to predict the clinical prognosis.

[Evaluation of CT angiography vascular localization combined with refined three-dimensional printing in guiding the resection and reconstruction of complex oral cancer]

Objective: To evaluate the effect of vascular localization using computerized tomography angiography (CTA) combined with refined three dimensional (3D) printing in guiding the resection and reconstruction of complex oral cancer. Methods: From December 2013 to July 2017, the clinical data of 30 patients with complex oral cancer enrolled in the Hunan Cancer Hospital were retrospectively analyzed. 15 patients received CTA+ 3D assisted surgery, while the other 15 patients underwent traditional surgery. In CTA+ 3D assisted surgery group, CT and Magnetic Resonance Imaging (MRI) data were combined with CTA to print refined solid 3D model and surgical guide plate. The preoperative and intraoperative virtual surgical system and the operative experience were combined for preoperative evaluation and surgery. In traditional surgery group, preoperative evaluation and surgery were performed according to imaging data and surgeons' clinical experience. Operative time, intraoperative blood loss, hospital stay and local recurrence rate were compared between the two groups. Results: In CTA+ 3D assisted surgery group, one patient gave up surgical treatment after intuitively watching the lesion through the 3D model, and the remaining 14 patients underwent surgery as planned. All the 15 patients in traditional surgery group received surgery. But the preoperative plans of three patients were temporarily and passively modified due to insufficient preoperative evaluation. The average intraoperative blood loss was(320.1±27.2)ml in CTA+ 3D assisted surgery group and(430.2±30.3)ml in traditional surgery group. Mean operation time was(440.3±19.2)min and(552.2±23.3)min, respectively. Mean hospitalization time was (20.4±3.2)d and (25.1±3.7)d, respectively. The differences were all statistically significant (all P<0.05). 1 year and 3 years local recurrence rates were 9.1% and 28.6% in CTA+ 3D assisted surgery group, as well as 14.3% and 50.4% in traditional surgery group with statistical significance (P<0.05). Conclusion: For complex oral cancer patients with difficulty in opening the mouth or postoperative recurrence, CTA vascular localization combined with fine 3D printing technology has significant advantages in the surgical process, surgical effect and postoperative evaluation index compared with traditional method using imaging data and clinical experience.

Study of e^{+}e^{-}→γωJ/ψ and Observation of X(3872)→ωJ/ψ

We study the e^{+}e^{-}→γωJ/ψ process using 11.6  fb^{-1} e^{+}e^{-} annihilation data taken at center-of-mass energies from sqrt[s]=4.008  GeV to 4.600 GeV with the BESIII detector at the BEPCII storage ring. The X(3872) resonance is observed for the first time in the ωJ/ψ system with a significance of more than 5σ. The relative decay ratio of X(3872)→ωJ/ψ and π^{+}π^{-}J/ψ is measured to be R=1.6_{-0.3}^{+0.4}±0.2, where the first uncertainty is statistical and the second systematic (the same hereafter). The sqrt[s]-dependent cross section of e^{+}e^{-}→γX(3872) is also measured and investigated, and it can be described by a single Breit-Wigner resonance, referred to as the Y(4200), with a mass of 4200.6_{-13.3}^{+7.9}±3.0  MeV/c^{2} and a width of 115_{-26}^{+38}±12  MeV. In addition, to describe the ωJ/ψ mass distribution above 3.9  GeV/c^{2}, we need at least one additional Breit-Wigner resonance, labeled as X(3915), in the fit. The mass and width of the X(3915) are determined. The resonant parameters of the X(3915) agree with those of the Y(3940) in B→KωJ/ψ and of the X(3915) in γγ→ωJ/ψ observed by the Belle and BABAR experiments within errors.

Observation of the Decay X(3872)→π^{0}χ_{c1}(1P)

Using a total of 9.0  fb^{-1} of e^{+}e^{-} collision data with center-of-mass energies between 4.15 and 4.30 GeV collected by the BESIII detector, we search for the processes e^{+}e^{-}→γX(3872) with X(3872)→π^{0}χ_{cJ} for J=0, 1, 2. We report the first observation of X(3872)→π^{0}χ_{c1}, a new decay mode of the X(3872), with a statistical significance of more than 5σ for all systematic fit variations. Normalizing to the previously established process e^{+}e^{-}→γX(3872) with X(3872)→π^{+}π^{-}J/ψ, we find B(X(3872)→π^{0}χ_{c1})/B(X(3872)→π^{+}π^{-}J/ψ)=0.88_{-0.27}^{+0.33}±0.10, where the first error is statistical and the second is systematic. We set 90% confidence level upper limits on the corresponding ratios for the decays to π^{0}χ_{c0} and π^{0}χ_{c2} of 19 and 1.1, respectively.

Precision Measurement of the Branching Fractions of η^{'} Decays

Based on a sample of (1310.6±7.0)×10^{6}J/ψ events collected with the BESIII detector, we present measurements of J/ψ and η^{'} absolute branching fractions using the process J/ψ→γη^{'}. By analyzing events where the radiative photon converts into an e^{+}e^{-} pair, the branching fraction for J/ψ→γη^{'} is measured to be (5.27±0.03±0.05)×10^{-3}. The absolute branching fractions of the five dominant decay channels of the η^{'} are then measured for the first time and are determined to be B(η^{'}→γπ^{+}π^{-})=(29.90±0.03±0.55)%, B(η^{'}→ηπ^{+}π^{-})=(41.24±0.08±1.24)%, B(η^{'}→ηπ^{0}π^{0})=(21.36±0.10±0.92)%, B(η^{'}→γω)=(2.489±0.018±0.074)%, and B(η^{'}→γγ)=(2.331±0.012±0.035)%, where the first uncertainties are statistical and the second systematic.

Measurement of the Dynamics of the Decays D_{s}^{+}→η^{(')}e^{+}ν_{e}

Using e^{+}e^{-} annihilation data corresponding to an integrated luminosity of 3.19  fb^{-1} collected at a center-of-mass energy of 4.178 GeV with the BESIII detector, we measure the absolute branching fractions B_{D_{s}^{+}→ηe^{+}ν_{e}}=(2.323±0.063_{stat}±0.063_{syst})% and B_{D_{s}^{+}→η^{'}e^{+}ν_{e}}=(0.824±0.073_{stat}±0.027_{syst})% via a tagged analysis technique, where one D_{s} is fully reconstructed in a hadronic mode. Combining these measurements with previous BESIII measurements of B_{D^{+}→η^{(')}e^{+}ν_{e}}, the η-η^{'} mixing angle in the quark flavor basis is determined to be ϕ_{P}=(40.1±2.1_{stat}±0.7_{syst})°. From the first measurements of the dynamics of D_{s}^{+}→η^{(')}e^{+}ν_{e} decays, the products of the hadronic form factors f_{+}^{η^{(')}}(0) and the Cabibbo-Kobayashi-Maskawa matrix element |V_{cs}| are determined with different form factor parametrizations. For the two-parameter series expansion, the results are f_{+}^{η}(0)|V_{cs}|=0.4455±0.0053_{stat}±0.0044_{syst} and f_{+}^{η^{'}}(0)|V_{cs}|=0.477±0.049_{stat}±0.011_{syst}.

Evidence of a Resonant Structure in the e^{+}e^{-}→π^{+}D^{0}D^{*-} Cross Section between 4.05 and 4.60 GeV

The cross section of the process e^{+}e^{-}→π^{+}D^{0}D^{*-} for center-of-mass energies from 4.05 to 4.60 GeV is measured precisely using data samples collected with the BESIII detector operating at the BEPCII storage ring. Two enhancements are clearly visible in the cross section around 4.23 and 4.40 GeV. Using several models to describe the dressed cross section yields stable parameters for the first enhancement, which has a mass of 4228.6±4.1±6.3  MeV/c^{2} and a width of 77.0±6.8±6.3  MeV, where the first uncertainties are statistical and the second ones are systematic. Our resonant mass is consistent with previous observations of the Y(4220) state and the theoretical prediction of a DD[over ¯]_{1}(2420) molecule. This result is the first observation of Y(4220) associated with an open-charm final state. Fits with three resonance functions with additional Y(4260), Y(4320), Y(4360), ψ(4415), or a new resonance do not show significant contributions from either of these resonances. The second enhancement is not from a single known resonance. It could contain contributions from ψ(4415) and other resonances, and a detailed amplitude analysis is required to better understand this enhancement.

[Clinicopathological features and prognosis of ALK-positive Spitz tumors]

Objective: To investigate the clinicopathologic features and prognosis of ALK-positive Spitz tumors. Methods: Thirteen patients with ALK-positive Spitz tumors diagnosed at Shanghai Cancer Center, Fudan University from October 2016 to December 2017 were collected. All cases were routinely evaluated histopathological features in HE staining and detected ALK protein expression by immunohistochemistry. The ALK fusions of 7 cases were confirmed by fluorescence in situ hybridization (FISH).Follow-up data was collected. Results: The age of patients including 2 males and 11 females ranged from 4 to 47 years (mean 25 years). 12 patients were diagnosed with atypical Spitz tumors and 1 patient was diagnosed with Spitz nevus. Clinically, most lesions presented as papules or nodules, while a few lesions presented as plaques. Histologically, most tumors were exophytic (9/13). More than half of the tumors were amelanotic and the junctional component was mainly composed of melanocytic nests. Kamino bodies were not found. The bases of the tumors were mainly wedge-shaped (5/13) and flat (7/13). Eight tumors displayed mixed cell types, while 5 tumors were composed of only spindle cells. All the tumors showed a plexiform and/or intersecting fascicular growth pattern, and perineural extension was observed in 3 tumors. ALK immunohistochemistry showed diffuse and intense cytoplasmic staining in 13 cases, and 7 of them were detected by FISH to confirm the presence of ALK fusions. All patients were followed up for 7 to 21 months (median=12), with no recurrence or lymph node dissemination. Conclusions: Spitz tumors with ALK fusions have their special histopathologic features.ALK fusions mainly occur in Spitz nevi and atypical Spitz tumors. The follow-up data of the existing literatures and our research indicates that the prognosis of ALK-positive Spitz tumors may be good.

Determination of the Pseudoscalar Decay Constant f_{D_{s}^{+}} via D_{s}^{+}→μ^{+}ν_{μ}

Using a 3.19  fb^{-1} data sample collected at an e^{+}e^{-} center-of-mass energy of E_{cm}=4.178  GeV with the BESIII detector, we measure the branching fraction of the leptonic decay D_{s}^{+}→μ^{+}ν_{μ} to be B_{D_{s}^{+}→μ^{+}ν_{μ}}=(5.49±0.16_{stat}±0.15_{syst})×10^{-3}. Combining our branching fraction with the masses of the D_{s}^{+} and μ^{+} and the lifetime of the D_{s}^{+}, we determine f_{D_{s}^{+}}|V_{cs}|=246.2±3.6_{stat}±3.5_{syst}  MeV. Using the c→s quark mixing matrix element |V_{cs}| determined from a global standard model fit, we evaluate the D_{s}^{+} decay constant f_{D_{s}^{+}}=252.9±3.7_{stat}±3.6_{syst}  MeV. Alternatively, using the value of f_{D_{s}^{+}} calculated by lattice quantum chromodynamics, we find |V_{cs}|=0.985±0.014_{stat}±0.014_{syst}. These values of B_{D_{s}^{+}→μ^{+}ν_{μ}}, f_{D_{s}^{+}}|V_{cs}|, f_{D_{s}^{+}} and |V_{cs}| are each the most precise results to date.

First Measurement of the Form Factors in D_{s}^{+}→K^{0}e^{+}ν_{e} and D_{s}^{+}→K^{*0}e^{+}ν_{e} Decays

We report on new measurements of Cabibbo-suppressed semileptonic D_{s}^{+} decays using 3.19  fb^{-1} of e^{+}e^{-} annihilation data sample collected at a center-of-mass energy of 4.178 GeV with the BESIII detector at the BEPCII collider. Our results include branching fractions B(D_{s}^{+}→K^{0}e^{+}ν_{e})=[3.25±0.38(stat)±0.16(syst)]×10^{-3} and B(D_{s}^{+}→K^{*0}e^{+}ν_{e})=[2.37±0.26(stat)±0.20(syst)]×10^{-3}, which are much improved relative to previous measurements, and the first measurements of the hadronic form-factor parameters for these decays. For D_{s}^{+}→K^{0}e^{+}ν_{e}, we obtain f_{+}(0)=0.720±0.084(stat)±0.013(syst), and for D_{s}^{+}→K^{*0}e^{+}ν_{e}, we find form-factor ratios r_{V}=V(0)/A_{1}(0)=1.67±0.34(stat)±0.16(syst) and r_{2}=A_{2}(0)/A_{1}(0)=0.77±0.28(stat)±0.07(syst).

Observation of D^{+}→f_{0}(500)e^{+}ν_{e} and Improved Measurements of D→ρe^{+}ν_{e}

Using a data sample corresponding to an integrated luminosity of 2.93  fb^{-1} recorded by the BESIII detector at a center-of-mass energy of 3.773 GeV, we present an analysis of the decays D^{0}→π^{-}π^{0}e^{+}ν_{e} and D^{+}→π^{-}π^{+}e^{+}ν_{e}. By performing a partial wave analysis, the π^{+}π^{-} S-wave contribution to D^{+}→π^{-}π^{+}e^{+}ν_{e} is observed to be (25.7±1.6±1.1)% with a statistical significance greater than 10σ, besides the dominant P-wave contribution. This is the first observation of the S-wave contribution. We measure the branching fractions B(D^{0}→ρ^{-}e^{+}ν_{e})=(1.445±0.058±0.039)×10^{-3}, B(D^{+}→ρ^{0}e^{+}ν_{e})=(1.860±0.070±0.061)×10^{-3}, and B(D^{+}→f_{0}(500)e^{+}ν_{e},f_{0}(500)→π^{+}π^{-})=(6.30±0.43±0.32)×10^{-4}. An upper limit of B(D^{+}→f_{0}(980)e^{+}ν_{e},f_{0}(980)→π^{+}π^{-})<2.8×10^{-5} is set at the 90% confidence level. We also obtain the hadronic form factor ratios of D→ρe^{+}ν_{e} at q^{2}=0 assuming the single-pole dominance parametrization: r_{V}={[V(0)]/[A_{1}(0)]}=1.695±0.083±0.051, r_{2}={[A_{2}(0)]/[A_{1}(0)]}=0.845±0.056±0.039.

Solving the mystery of vanishing rivers in China

A major controversy was sparked worldwide by a recent national water census claiming that the number of Chinese rivers with watersheds ≥100 km2 was less than half the previous estimate of 50 000 rivers, which also stimulates debates on the potential causes and consequences. Here, we estimated the number of rivers in terms of stream-segmentation characteristics described by Horton, Strahler and Shreve stream-order rules, as well as their mixed mode for named rivers recorded in the Encyclopedia of Rivers and Lakes in China. As a result, the number of ‘vanishing rivers’ has been found to be highly relevant to statistical specifications in addition to the erroneous inclusion of pseudo-rivers primarily generated in arid or frost-thaw areas. The modified Horton stream-order scheme reasonably depicts the configuration of complete natural streams from headwater to destination, while the Strahler largely projects the fragmentation of the named river networks associated with human aggregation to the hierarchical river systems.