Could the 21-cm absorption be explained by the dark matter suggested by 8^8Be transitions?

The stronger than expected 21-cm absorption was observed by EDGES recently, and another anomaly of $^8$Be transitions would be signatures of new interactions. These two issues may be related to each other, e.g., pseudoscalar $A$ mediated fermionic millicharged dark matter (DM), and the 21-cm absorption could be induced by photon mediated scattering between MeV millicharged DM and hydrogen. This will be explored in this paper. For fermionic millicharged DM $\bar{\chi} \chi$ with masses in a range of $2 m_A < 2 m_{\chi} < 3 m_A$, the p-wave annihilation $\bar{\chi} \chi \to A A$ would be dominant during DM freeze-out. The s-wave annihilation $\bar{\chi} \chi$ $\to A, \gamma$ $\to e^+ e^-$ is tolerant by constraints from CMB and the 21-cm absorption. The millicharged DM can evade constraints from direct detection experiments. The process of $K^+ \to \pi^+ \pi^0$ with the invisible decay $\pi^0 \to \bar{\chi} \chi$ could be employed to search for the millicharged DM, and future high intensity $K^+$ sources, such as NA62, will do the job.Comment: 6 pages, 2 figures, the accepted version, EPJ

On Block Cholesky Decomposition for Sparse Inverse Covariance Estimation

The modified Cholesky decomposition is popular for inverse covariance estimation, but often needs pre-specification on the full information of variable ordering. In this work, we propose a block Cholesky decomposition (BCD) for estimating inverse covariance matrix under the partial information of variable ordering, in the sense that the variables can be divided into several groups with available ordering among groups, but variables within each group have no orderings. The proposed BCD model provides a unified framework for several existing methods including the modified Cholesky decomposition and the Graphical lasso. By utilizing the partial information on variable ordering, the proposed BCD model guarantees the positive definiteness of the estimated matrix with statistically meaningful interpretation. Theoretical results are established under regularity conditions. Simulation and case studies are conducted to evaluate the proposed BCD model

O legado colonial japonês e suas atuais implicações políticas no estreito de Taiwan

Although the majority of Taiwan’s population is descended from Chinese settlers who immigrated to the island between the 17th and 19th centuries, the Taiwanese independence movements refuse to accept unification with China, that since its founding in 1949 has claimed Taiwan as its own territory, and insist on designating Taiwan as a separate independent political entity from China. However, the existence of these independence movements is relatively new and begun in the mid-twentieth century, after the end of the fiftieth year of Japanese colonization in 1945. This article aims to analyse how the Japanese colonial and post-colonial experience played an important role in changing the perception of national identity in Taiwan, and currently is the main source of tension in relations with China. The article concludes that the fifty years of Japanese colonization and the violent Chinese repression in the post-war period were essential for the formation of a Taiwanese national identity distinct from the Chinese one and for the emergence of the Taiwanese independence movements.Embora a maior parte da população de Taiwan seja descendente de colonos chineses que imigram para a ilha entre os séculos XVII e XIX, os movimentos de independência de Taiwan se recusam a aceitar a unificação com a China, que desde a sua fundação em 1949 reivindica Taiwan como seu próprio território, e insistem em designar Taiwan como uma entidade política separada e independente da China. No entanto, a existência desses movimentos é relativamente recente e ocorreu partir de meados do século XX, após o fim dos cinquenta anos da colonização japonesa em 1945. O presente artigo tem o objetivo de analisar como a experiência colonial e pós-colonial japonesa tiveram o papel fundamental para a mudança da percepção de identidade nacional em Taiwan, atualmente a principal fonte de tensões nas relações com a China. O artigo conclui que os cinquenta anos de colonização japonesa e a violenta repressão chinesa no período pós-guerra, foram essenciais para a formação da identidade nacional taiwanesa distinta da chinesa e para o surgimento dos movimentos de independência de Taiwan

A democratização de Taiwan e suas implicações nas relações com os Estados Unidos e com a China

Após quase quatro décadas de tranquilidade no estreito de Taiwan, a paz no estreito foi subitamente interrompida em 1995, quando a China lançou uma série de testes com mísseis balísticos contra a costa taiwanesa. A partir de 1995, a China passou a acusar as autoridades de Taiwan de promover a “independência” de Taiwan, e por inúmeras vezes ameaçou Taiwan de guerra. Durante este mesmo período, observou-se o rápido crescimento do nacionalismo taiwanês, fato que influenciou diretamente as recentes crises no estreito de Taiwan. Esta monografia demonstra que as recentes crises (1988-2008), foram resultados diretos da democratização de Taiwan ao final da década de 1980, que aprofundou o histórico conflito entre os dois principais grupos étnico e antagônicos de Taiwan, refletindo-se na política interna e externa de Taiwan

Stream Monitoring and Preliminary Co-Treatment of Acid Mine Drainage and Municipal Wastewater along Dunkard Creek Area

This study investigated coal-mine drainage (AMD) and municipal wastewater (MWW) contaminant concentrations and conducted the combined treatment in phases I and II: phase I, evaluating the effects of mixing the two based on the extent of acid neutralization and metals removal; phase II: conducting anaerobic batch reactor treatment of AMD and MWW under varying COD/sulfate ratios (0.04-5.0). In phase I, acid mine drainage water quality conditions are as follows: pH 4.5, acidity 467.5 mg/L as CaCO3, alkalinity 96.0 mg/L as CaCO3, Cl- 11.8 mg/L, SO4 2- 1722 mg/L, TDS 2757.5 mg/L, TSS 9.8 mg/L, BOD 14.7 mg/L, Fe 138.1 mg/L, Mg 110.8 mg/L. Mn 7.5 mg/L, Al 8.1 mg/L, Na 114.2 mg/L, and Ca 233.5 mg/L. Results of the mixing experiments indicated significant removal of selected metals (Fe 85~98%, Mg 0~65%, Mn 63~89%, Al 98~99%, Na 0~30%), acidity (77~95%) from the mine water and pH was raised to above 6.3. The Phase II results suggested under the wide range of COD/ sulfate ratios, COD and sulfate removal varied from 37.4%-100% and 0%-93.5% respectively. During biological treatment, alkalinity was generated which leads to pH increase to around 7.6-8.5. The results suggested feasibility of the proposed technology for co-treatment of AMD and MWW. A conceptual design of co-treatment system which is expected to remove a matrix of pollutants has been provided to utilize all the locally available water resources to achieve the optimum treatment efficiency. The technology also offers an opportunity to significantly reduce capital and operating costs compared to the existing treatment methodologies used. Featured Application: In this study, we have measured the concentrations of contaminants in acid mine drainage (AMD) and municipal wastewater (MWW) and conducted the combined treatment in phases I and II. This is significant because in previous years there was a massive fish kill that is linked to the high total dissolved solids (TDS) and salinity content in the water. With the current proposed combined treatment technology, it shows high potential in reducing TDS and salinity content in the combined wastewater which will prevent similar accident (Dunkard creek fish kill in 2019) happening again

Periodic and uniform nanogratings formed on cemented carbide by femtosecond laser scanning

Periodic and uniform nanogratings are fabricated by femtosecond laser scanning on cemented carbide. Specifically, three experiments are designed to study the influence of single pulse energy, scanning speed, and scanning spacing on the period and the uniformity of the formed nanogratings. The results show that the sample with single pulse energy of 2 μJ, scanning speed of 1000 μm/s, and scanning spacing of 5 μm shows the best quality of nanogratings among all the tested samples at different processing parameters. The uniformity of the nanogratings is largely determined by single pulse energy, scanning speed, and scanning spacing. Single pulse energy and scanning speed significantly affect the period of the nanogratings, whereas the period of the nanogratings maintains a fixed value under different scanning spacings. The period of the nanogratings increases gradually with the decrease of the single pulse energy and the increase of the scanning speed, respectively

Preventing olanzapine-induced weight gain using betahistine: a study in a rat model with chronic olanzapine treatment

Olanzapine is the one of first line antipsychotic drug for schizophrenia and other serious mental illness. However, it is associated with troublesome metabolic side-effects, particularly body weight gain and obesity. The antagonistic affinity to histamine H1 receptors (H1R) of antipsychotic drugs has been identified as one of the main contributors to weight gain/obesity side-effects. Our previous study showed that a short term (2 weeks) combination treatment of betahistine (an H1R agonist and H3R antagonist) and olanzapine (O+B) reduced (−45%) body weight gain induced by olanzapine in drug-naïve rats. A key issue is that clinical patients suffering with schizophrenia, bipolar disease and other mental disorders often face chronic, even life-time, antipsychotic treatment, in which they have often had previous antipsychotic exposure. Therefore, we investigated the effects of chronic O+B co-treatment in controlling body weight in female rats with chronic and repeated exposure of olanzapine. The results showed that co-administration of olanzapine (3 mg/kg, t.i.d.) and betahistine (9.6 mg/kg, t.i.d.) significantly reduced (−51.4%) weight gain induced by olanzapine. Co-treatment of O+B also led to a decrease in feeding efficiency, liver and fat mass. Consistently, the olanzapine-only treatment increased hypothalamic H1R protein levels, as well as hypothalamic pAMPKα, AMPKα and NPY protein levels, while reducing the hypothalamic POMC, and UCP1 and PGC-1α protein levels in brown adipose tissue (BAT). The olanzapine induced changes in hypothalamic H1R, pAMPKα, BAT UCP1 and PGC-1α could be reversed by co-treatment of O+B. These results supported further clinical trials to test the effectiveness of co-treatment of O+B for controlling weight gain/obesity side-effects in schizophrenia with chronic antipsychotic treatment

Unique effects of acute aripiprazole treatment on the dopamine D2 receptor downstream cAMP-PKA and Akt-GSK3β signalling pathways in rats

Aripiprazole is a wide-used antipsychotic drug with therapeutic effects on both positive and negative symptoms of schizophrenia, and reduced side-effects. Although aripiprazole was developed as a dopamine D2 receptor (D2R) partial agonist, all other D2R partial agonists that aimed to mimic aripiprazole failed to exert therapeutic effects in clinic. The present in vivo study aimed to investigate the effects of aripiprazole on the D2R downstream cAMP-PKA and Akt-GSK3β signalling pathways in comparison with a D2R antagonist - haloperidol and a D2R partial agonist - bifeprunox. Rats were injected once with aripiprazole (0.75mg/kg, i.p.), bifeprunox (0.8mg/kg, i.p.), haloperidol (0.1mg/kg, i.p.) or vehicle. Five brain regions - the prefrontal cortex (PFC), nucleus accumbens (NAc), caudate putamen (CPu), ventral tegmental area (VTA) and substantia nigra (SN) were collected. The protein levels of PKA, Akt and GSK3β were measured by Western Blotting; the cAMP levels were examined by ELISA tests. The results showed that aripiprazole presented similar acute effects on PKA expression to haloperidol, but not bifeprunox, in the CPU and VTA. Additionally, aripiprazole was able to increase the phosphorylation of GSK3β in the PFC, NAc, CPu and SN, respectively, which cannot be achieved by bifeprunox and haloperidol. These results suggested that acute treatment of aripiprazole had differential effects on the cAMP-PKA and Akt-GSK3β signalling pathways from haloperidol and bifeprunox in these brain areas. This study further indicated that, by comparison with bifeprunox, the unique pharmacological profile of aripiprazole may be attributed to the relatively lower intrinsic activity at D2R