Possible Deuteron-like Molecular States Composed of Heavy Baryons

We perform a systematic study of the possible loosely bound states composed of two charmed baryons or a charmed baryon and an anti-charmed baryon within the framework of the one boson exchange (OBE) model. We consider not only the $\pi$ exchange but also the $\eta$, $\rho$, $\omega$, $\phi$ and $\sigma$ exchanges. The $S-D$ mixing effects for the spin-triplets are also taken into account. With the derived effective potentials, we calculate the binding energies and root-mean-square (RMS) radii for the systems $\Lambda_c\Lambda_c(\bar{\Lambda}_c)$, $\Xi_c\Xi_c(\bar{\Xi}_c)$, $\Sigma_c\Sigma_c(\bar{\Sigma}_c)$, $\Xi_c^\prime\Xi_c^\prime(\bar{\Xi}_c^\prime)$ and $\Omega_c\Omega_c(\bar{\Omega}_c)$. Our numerical results indicate that: (1) the H-dibaryon-like state $\Lambda_c\Lambda_c$ does not exist; (2) there may exist four loosely bound deuteron-like states $\Xi_c\Xi_c$ and $\Xi_c^\prime\Xi_c^\prime$ with small binding energies and large RMS radii.Comment: 17 pages, 32 figure

Observation of prolonged coherence time of the collective spin wave of atomic ensemble in a paraffin coated Rb vapor cell

We report a prolonged coherence time of the collective spin wave of a thermal 87Rb atomic ensemble in a paraffin coated cell. The spin wave is prepared through a stimulated Raman Process. The long coherence time time is achieved by prolonging the lifetime of the spins with paraffin coating and minimize dephasing with optimal experimental configuration. The observation of the long time delayed-stimulated Stokes signal in the writing process suggests the prolonged lifetime of the prepared spins; a direct measurement of the decay of anti-Stokes signal in the reading process shows the coherence time is up to 300 us after minimizing dephasing. This is one hundred times longer than the reported coherence time in the similar experiments in thermal atomic ensembles based on the Duan-Lukin-Cirac-Zoller (DLCZ) and its improved protocols. This prolonged coherence time sets the upper limit of the memory time in quantum repeaters based on such protocols, which is crucial for the realization of long-distance quantum communication. The previous reported fluorescence background in the writing process due to collision in a sample cell with buffer gas is also reduced in a cell without buffer gas.Comment: 4 pages, 4 figure

Nexus between green financing, economic risk, political risk and environment: evidence from China

This study provides fresh evidence regarding the dynamic association that is believed to exist in relation to green finance (GF), economic growth (GDP), political risk (PR), economic risk (ER), and carbon dioxide (CO2) emissions. It therefore uses the dataset pertaining to China from most recent time-series – covering the period spanning from the years of 1990 to 2020, by employing the Morlet Wavelet Analysis technique. The empirical findings of the wavelet power spectrum reveal that green finance GF and ER are vulnerable in the short- and long-run, and the short-run, respectively. At the same time, no vulnerability has been observed in the GDP, PR, and CO2 emissions. In addition to this, the wavelet coherence also reveals the bidirectional causal association that exists between GF-CO2 and ER-CO2, but only in the short run. It must also be taken into consideration that the causal influence of CO2 is deemed to be greater than the GF and ER, respectively. Besides this, a bidirectional causal nexus also exists between the GDP and CO2 emissions, only in the long run. Furthermore, the association between the economic growths follows both the phase and antiphase associations. Moreover, the study also reveals that there is no significant causal link between the PR and CO2 emissions. The results emphasize that the significance of green finance investment will tend to increase with strict policy implications, stabilization or minimization of economic risk and political risk. The same will also take place while promoting environmentally friendly production via economic growth, so as to reduce CO2 emission in the region taken into account

Clinical analysis of kasabach-merritt syndrome in 17 neonates

BACKGROUND: Kasabach-Merritt syndrome (KMS) is characterized by giant hemangiomas and severe thrombocytopenia, which may result in life-threatening multi-organ hemorrhage. This study evaluated the clinical characteristics, treatments, and outcomes in neonates with KMS, in order to find out the optimal therapy. METHODS: The clinical data of 17 patients treated for KMS in the Department of Neonates, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, China from January 2007 to January 2012 were retrospectively analyzed. RESULTS: The patients were 13 males and 4 females, aged 17 hours to 28 days at admission. Four patients had visceral hemangiomas and 13 had cutaneous hemangiomas. All had thrombocytopenia and coagulation disorders. Intravenous steroid therapy was initially effective in 6 patients (of which 3 relapsed) and ineffective in 11. The 11 patients with a poor response to steroids and the 3 who relapsed underwent arterial embolization therapy, which was effective in 9 patients (of which 1 relapsed), ineffective in 4, and discontinued before completion in 1. Subsequently, four patients in whom arterial embolization therapy was ineffective and one with relapse were treated with vincristine. This was effective in four patients, and the other died of disseminated intravascular coagulation. Steroid therapy was effective in 35.3% of patients, but the relapse rate was 50%. Arterial embolization was effective in 64.3% of patients and vincristine was effective in 80%. CONCLUSIONS: In patients with neonatal KMS, steroid therapy has a low rate of effectiveness and high rate of relapse. Arterial embolization has a good rate of effectiveness. Combined steroid and embolization therapy should be considered for first-line treatment of neonatal KMS. If this approach is ineffective, vincristine may be useful

Dynamic behavior of a vehicle with rear axle compliance steering

Rear axle compliance steering (RACS) is a technology of passive four-wheel steering, which is designed to improve the vehicle handling and stability at medium or high speed. This paper focuses on the dynamic behavior of the vehicle with RACS. Firstly, the compliance steering principle for different rear suspensions is illustrated. Then, the viscoelastic members with fractional order derivative properties are introduced into RACS, and the fractional order model of RACS is formulated. Next, the dynamic model of the vehicle with RACS is established, the adjusting rules for the compliance steering stiffness are derived, and the vehicle stability is investigated. Finally, numerical experiments are performed to illustrate the effects on the vehicle dynamic behavior caused by the compliance steering stiffness, the viscoelastic members and the vehicle longitudinal velocity. Research results show that, the vehicle with RACS has better dynamic characteristics than that without RACS at medium or high speed; and the compliance steering stiffness, the viscoelastic members and the vehicle longitudinal velocity have different impacts on the vehicle lateral dynamic behavior