Statistical computation of Boltzmann entropy and estimation of the optimal probability density function from statistical sample

In this work, we investigate the statistical computation of the Boltzmann entropy of statistical samples. For this purpose, we use both histogram and kernel function to estimate the probability density function of statistical samples. We find that, due to coarse-graining, the entropy is a monotonic increasing function of the bin width for histogram or bandwidth for kernel estimation, which seems to be difficult to select an optimal bin width/bandwidth for computing the entropy. Fortunately, we notice that there exists a minimum of the first derivative of entropy for both histogram and kernel estimation, and this minimum point of the first derivative asymptotically points to the optimal bin width or bandwidth. We have verified these findings by large amounts of numerical experiments. Hence, we suggest that the minimum of the first derivative of entropy be used as a selector for the optimal bin width or bandwidth of density estimation. Moreover, the optimal bandwidth selected by the minimum of the first derivative of entropy is purely data-based, independent of the unknown underlying probability density distribution, which is obviously superior to the existing estimators. Our results are not restricted to one-dimensional, but can also be extended to multivariate cases. It should be emphasized, however, that we do not provide a robust mathematical proof of these findings, and we leave these issues with those who are interested in them.Comment: 8 pages, 6 figures, MNRAS, in the pres

Influence of the Process Parameters on the Formation of CaSO 4

This paper discussed the influence of the process parameters such as the temperature, the mixing ways, and the molar ratios of the reactants on the morphology of the CaSO4·2H2O precursors and the CaSO4·0.5H2O whiskers. The experimental results indicated that CaSO4·0.5H2O whiskers with a length of 80–310 μm and a width of 0.8–8.0 μm were produced at hydrothermal condition, using CaSO4·2H2O fine particles as the precursors which were formed by adding Na2SO4 solution into CaCl2 solution at 25°C at the molar ratio of Na2SO4 to CaCl2 being 0.5 : 1. A lower supersaturation and a higher [Ca2+]/[] molar ratio favored the formation of CaSO4·2H2O particles with small sizes and the hydrothermal synthesis of CaSO4·0.5H2O whiskers with high aspect ratios

A systematic study on the binding energy of Λ\Lambda hypernuclei

In this paper, we calculated the binding energy per baryon of the $\Lambda$ hypernuclei systemically, using the relativistic mean field theory (RMF) in a statistic frame. Some resemble properties are found among most of the hypernuclei found in experiments. The data show that a $\Lambda$ hypernucleus will be more stable, if it is composed of a $\Lambda$ hyperon adding to a stable normal nuclear core, or a $\Lambda$ hyperon replacing a neutron in a stable normal nuclear core. According to our calculations, existences of some new $\Lambda$ hypernuclei are predicted under the frame of RMF.Comment: 8 pages, 6 figures, 3 table

Primary carcinoid tumor of the gallbladder: A case report and brief review of the literature

<p>Abstract</p> <p>Background</p> <p>Primary carcinoid tumor of the gallbladder is rare and comprises less than 1% of all carcinoid tumors. Preoperative diagnosis of carcinoid tumor of the gallbladder is difficult. The imageology findings are similar to those in other gallbladder cancers.</p> <p>Case presentation</p> <p>A 46-year-old woman was hospitalized with a preoperative diagnosis of gallbladder carcinoma, The patient was referred for surgical opinion and laparotomy was subsequently performed. A 4 × 5 cm mass was found within the gallbladder, located on the free surface of the body and fundus of the gallbladder. Neither metastases nor direct invasion to the liver was found. The entire mass and gallbladder were excised and intact. Histologically, the tumor consisted of small oval cells with round-to-oval neclei and tumor cells formed small nodular, trabeculare and acinar structures. The tumor showed moderate pleomorphism with scattered mitotic figures, but no definite evidence of vascular permeation, perineural invasion or lymphatic permeation was seen. The tumor cells invaded the mucosa extensively, and some penetrated the muscular layer but not through the serosa of the gallbladder into the liver. Immunohistochemical studies revealed strong positive reaction for chromogranin A and NSE. This lesion was proved to be a primary carcinoid tumor of the gallbladder. A brief review of literature, clinical feature, pathology and treatment of this rare disease was discussed.</p> <p>Conclusion</p> <p>Primary carcinoid tumor of the gallbladder is uncommon. The definite diagnosis is often made on histopathological results after surgery.</p

Heavy Metals Migration in Soil in Tailing Dam Region of Shuikoushan, Hunan Province, China

AbstractThe nonferrous mining industry in China has been exploiting rich domestic mineral resources in order to sustain rapidly economic and social development. The paper chooses the tailing dam region as the research object in the Shuikoushan, and researches the distribution of Pb, Zn, Cu, Cd, As, Cr, which reveals heavy metal migration regularities in layers from new and old tailing dam region. In addition, this article focuses on making the research of Potential Ecological Risk Index appraisal to the heavy metal contamination level. The results showed that the concentrations of heavy metals in old tailing dam region were much higher than those of in the new tailing dam region. As well, the concentrations of most heavy metal reduced progressively with the soil depth increasing for the new tailing dam region, while the change tendency was inversely for the old one. Potential ecological risk index showed that the potential ecological risks were at low and low to moderate level in tailing dam region

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

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

Use of low-dose computed tomography to assess pulmonary tuberculosis among healthcare workers in a tuberculosis hospital

BACKGROUND: According to the World Health Organization, China is one of 22 countries with serious tuberculosis (TB) infections and one of the 27 countries with serious multidrug-resistant TB strains. Despite the decline of tuberculosis in the overall population, healthcare workers (HCWs) are still at a high risk of infection. Compared with high-income countries, the TB prevalence among HCWs is higher in low- and middle-income countries. Low-dose computed tomography (LDCT) is becoming more popular due to its superior sensitivity and lower radiation dose. However, there have been no reports about active pulmonary tuberculosis (PTB) among HCWs as assessed with LDCT. The purposes of this study were to examine PTB statuses in HCWs in hospitals specializing in TB treatment and explore the significance of the application of LDCT to these workers. METHODS: This study retrospectively analysed the physical examination data of healthcare workers in the Beijing Chest Hospital from September 2012 to December 2015. Low-dose lung CT examinations were performed in all cases. The comparisons between active and inactive PTB according to the CT findings were made using the Pearson chi-square test or the Fisher’s exact test. Comparisons between the incidences of active PTB in high-risk areas and non-high-risk areas were performed using the Pearson chi-square test. Analyses of active PTB were performed according to different ages, numbers of years on the job, and the risks of the working areas. Active PTB as diagnosed by the LDCT examinations alone was compared with the final comprehensive diagnoses, and the sensitivity and positive predictive value were calculated. RESULTS: A total of 1 012 participants were included in this study. During the 4-year period of medical examinations, active PTB was found in 19 cases, and inactive PTB was found in 109 cases. The prevalence of active PTB in the participants was 1.24%, 0.67%, 0.81%, and 0.53% for years 2012 to 2015. The corresponding incidences of active PTB among the tuberculosis hospital participants were 0.86%, 0.41%, 0.54%, and 0.26%. Most HCWs with active TB (78.9%, 15/19) worked in the high-risk areas of the hospital. There was a significant difference in the incidences of active PTB between the HCWs who worked in the high-risk and non-high-risk areas (odds ratio [OR], 14.415; 95% confidence interval (CI): 4.733 – 43.896). Comparisons of the CT signs between the active and inactive groups via chi-square tests revealed that the tree-in-bud, cavity, fibrous shadow, and calcification signs exhibited significant differences (P = 0.000, 0.021, 0.001, and 0.024, respectively). Tree-in-bud and cavity opacities suggest active pulmonary tuberculosis, whereas fibrous shadow and calcification opacities are the main features of inactive pulmonary tuberculosis. Comparison with the final comprehensive diagnoses revealed that the sensitivity and positive predictive value of the diagnoses of active PTB based on LDCT alone were 100% and 86.4%, respectively. CONCLUSIONS: Healthcare workers in tuberculosis hospitals are a high-risk group for active PTB. Yearly LDCT examinations of such high-risk groups are feasible and necessary. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s40249-017-0274-6) contains supplementary material, which is available to authorized users