Lattice Boltzmann method for weakly ionized isothermal plasmas

In this paper, a lattice Boltzmann method (LBM) for weakly ionized isothermal plasmas is presented by introducing a rescaling scheme for the Boltzmann transport equation. Without using this rescaling, we found that the nondimensional relaxation time used in the LBM is too large and the LBM does not produce physically realistic results. The developed model was applied to the electrostatic wave problem and the diffusion process of singly ionized helium plasmas with a 1-3% degree of ionization under an electric field. The obtained results agree well with theoretical values.open8

Radiolarian assemblages related to the ocean–ice interaction around the East Antarctic coast

The Southern Ocean plays a central role in Earth's climate, ecology, and biogeochemical cycles. Therefore, understanding long-term changes in Southern Ocean water masses in the geologic past is essential for assessing the role of the Southern Ocean in the climate system. Radiolarian fossils are a useful tool to reconstruct the water masses of the Southern Ocean. However, the radiolarian assemblages in the high latitudes of the Southern Ocean (south of the polar front (PF)) are still poorly understood. In this paper, we report the radiolarian assemblages in surface marine sediment and plankton tow samples collected from the high latitudes south of the PF. In the surface sediments, four factors (named F1–F4) of the radiolarian assemblages were identified using Q-mode factor analysis, which are related to different water masses and hydrological conditions. F1 is related to the surface waters south of the southern boundary (SB) of the Antarctic Circumpolar Current (ACC), which are cooled by melting sea ice and ice sheets. F2 is associated with water masses north of the SB. A comparison with the vertical distribution of the radiolarian assemblages in plankton tow samples indicates that characteristic species are associated with the Circumpolar Deep Water (CDW) and surface waters north of the SB. F3 is associated with modified Circumpolar Deep Water (mCDW). The radiolarian assemblage of F4 does not seem specifically related to any of the water mass here analyzed. However, the species in this assemblage are typically dwells within ice shelf and/or sea ice edge environments. Radiolarian assemblages here identified and associated with water masses, and ice edge environments are useful to reconstruct the environment south of the PF in the geologic past.</p

Hadal water biogeochemistry over the Izu–Ogasawara Trench observed with a full-depth CTD-CMS

Full-depth profiles of hydrographic and geochemical properties at the Izu–Ogasawara Trench were observed for the first time using a CTD-CMS (conductivity–temperature–depth profiler with carousel multiple sampling) system. Additionally, comparative samplings were done at the northern Mariana Trench using the same methods. A well-mixed hydrographic structure below 7000 m was observed within the Izu–Ogasawara Trench. Seawater samples collected from this well-mixed hadal layer exhibited constant concentrations of nitrate, phosphate, silicate, and nitrous oxide as well as constant nitrogen and oxygen isotopic compositions of nitrate and nitrous oxide. These results agree well with previous observations of the Izu–Ogasawara hadal waters and deep-sea water surrounding the Izu–Ogasawara Trench. In turn, methane concentrations and isotopic compositions indicated spatial heterogeneity within the well-mixed hadal water mass, strongly suggesting a local methane source within the trench, in addition to the background methane originating from the general deep-sea bottom water. Sedimentary compound releases, associated with sediment re-suspensions, are considered to be the most likely mechanism for generating this significant CH4 anomaly.</p

DCS liquid-based system is more effective than conventional smears to diagnosis of cervical lesions : study in high-risk population with biopsy-based confirmation

Objective. To compare the performances of Papanicolaou test (PapTest) and of a new liquid-based cytology method, DNA-CitoliqR System (DCS), in a high-risk population, with histology confirmation. Methods. Paired specimens of exfoliated cervical cells were collected under split-sample protocol. All patients were submitted to colposcopy and a biopsy taken when any atypical transformation zone was seen. Sensitivity, specificity, positive and negative predictive values, and overall accuracy of both conventional and DCS methods were computed in relation to histology. Results. A total of 1095 patients were analyzed by two cytology methods and, in 425 (38.8%), histologically. There were significantly more adequate samples with DCS (98.63%) than with conventional (89.6%) smears ( P < 0.001). ASCUS was diagnosed significantly more with DCS than with conventional Pap ( P < 0.001). Conventional Pap misclassified as normal 55.4% (158/285) of cases with either LSIL or HSIL or cancer at histology, whereas DCS misclassified 31.2% (89/285) of cases ( P < 0.001). DCS had a significantly higher sensitivity (70% and 91.3%) than the conventional Pap (49.8% and 72.8%) to detect both LSIL+ and HSIL+ at histology, respectively. On the other hand, specificity of conventional smear (88.2% and 85.2%) was significantly higher than DCS (75.4% and 70.9%) considering both LSIL+ and HSIL+ at histology, respectively. Conclusions. This study confirms the superiority of the liquid-based cytology system DCS to detect cervical lesions. The rate of adequate DSC slides was significantly higher than with conventional cytology

A Monte Carlo simulation of ion transport at finite temperatures

We have developed a Monte Carlo simulation for ion transport in hot background gases, which is an alternative way of solving the corresponding Boltzmann equation that determines the distribution function of ions. We consider the limit of low ion densities when the distribution function of the background gas remains unchanged due to collision with ions. A special attention has been paid to properly treat the thermal motion of the host gas particles and their influence on ions, which is very important at low electric fields, when the mean ion energy is comparable to the thermal energy of the host gas. We found the conditional probability distribution of gas velocities that correspond to an ion of specific velocity which collides with a gas particle. Also, we have derived exact analytical formulas for piecewise calculation of the collision frequency integrals. We address the cases when the background gas is monocomponent and when it is a mixture of different gases. The developed techniques described here are required for Monte Carlo simulations of ion transport and for hybrid models of non-equilibrium plasmas. The range of energies where it is necessary to apply the technique has been defined. The results we obtained are in excellent agreement with the existing ones obtained by complementary methods. Having verified our algorithm, we were able to produce calculations for Ar$^+$ ions in Ar and propose them as a new benchmark for thermal effects. The developed method is widely applicable for solving the Boltzmann equation that appears in many different contexts in physics.Comment: 14 page

Efficient recycling of nutrients in modern and past hypersaline environments

The biogeochemistry of hypersaline environments is strongly influenced by changes in biological processes and physicochemical parameters. Although massive evaporation events have occurred repeatedly throughout Earth history, their biogeochemical cycles and global impact remain poorly understood. Here, we provide the first nitrogen isotopic data for nutrients and chloropigments from modern shallow hypersaline environments (solar salterns, Trapani, Italy) and apply the obtained insights to δ15N signatures of the Messinian salinity crisis (MSC) in the late Miocene. Concentrations and δ15N of chlorophyll a, bacteriochlorophyll a, nitrate, and ammonium in benthic microbial mats indicate that inhibition of nitrification suppresses denitrification and anammox, resulting in efficient ammonium recycling within the mats and high primary productivity. We also suggest that the release of 15N-depleted NH3(gas) with increasing salinity enriches ammonium 15N in surface brine (≈34.0‰). Such elevated δ15N is also recorded in geoporphyrins isolated from sediments of the MSC peak (≈20‰), reflecting ammonium supply sufficient for sustaining phototrophic primary production. We propose that efficient nutrient supply combined with frequent bottom-water anoxia and capping of organic-rich sediments by evaporites of the Mediterranean MSC could have contributed to atmospheric CO2 reduction during the late Miocene.This study was partly supported by a Japan Society for the Promotion of Science (JSPS) Research Fellowship (16J07844) to YI, Grants-in-Aid (16H02236) and the JAMSTEC President Fund to NO

O impacto do diagnóstico citológico de atipiasi indeterminadas no sistema público de saúde

As alterações citológicas de significado indeterminado representam uma importante limitação diagnóstica nos programas de escrutíneo de lesões cérvico-vaginais. A introdução de métodos biomoleculares, como o sistema de captura híbrida para detecção de HPV de alto risco contribui para a otimização da conduta clínica dessas pacientes, indicando colposcopia com precisão. Objetivo: avaliar o significado de lesões de significado indeterminado com relação à infecção pelo HPV, com o uso do teste de DNA para HPV com o método da captura de híbridos II. Métodos: foram estudadas amostras de 236 casos consecutivos examinados no laboratório da DIGENE-BRASIL, de pacientes com diagnóstico citológico prévio de ASCUS. As amostras foram submetidas ao teste de captura híbrida para identificação de DNA-HPV de alto e baixo riscos. Resultados: dos 236 casos analisados, 183 (77,5%) foram negativos para o teste de captura híbrida, seis (2,6%) foram positivos para HPV de baixo risco e 47 (19,9%) foram positivos para HPV de alto risco. Conclusão : as amostras positivas para HPV de baixo risco representam uma pequena e não- onsiderável minoria de casos, provavelmente, transientes. Cerca de 20% dos casos foram positivos para HPV de alto risco e deverão ser encaminhados à colposcopia e biopsia, se necessário. Esses casos representam um grande potencial de progressão para lesões cervicais.In order to optimize the morphological analysis of the cases with uncertain diagnosis, we critically analyzed the cases with Atypia of Squamous Cells of Undertemined Significance (ASCUS) in cytological samples of uterine cervix collected in conventional smears (CS) and liquidbased preparations (LBC) an to correlate the findings with Hybrid Capture II (HC2) assay and biopsy. Objective: to evaluate the meanig of undetermined cytological atypia in relation to HPV infection detected by hybrid capture II test. Methods: 97 cases taken from women examined at Perola Byignton Hospital, São Paulo, Brazil, during the year of 2002. The conventional smears were taken previously than LBC. The residual sample was placed in liquid-medium and LBC preparation with DNA-Citoliq system was performed. If at least one of the paired samples were classified as ASCUS, the pair was submitted to a guided revision in order to evaluate the type of alteration taken in account to categorized ASCUS. Results: from 97 cases studied, 14 were categorized as ASCUS by the two methods simultaneously. The others had different classification under or hyper estimated. Six cases diagnosed as squamous intraepithelial lesion (SIL) by CS were ASCUS by LBC; in contrary, 19 ASCUS by CS were SIL by LBC. Eleven ASCUS by CS were diagnosed as negative by LBC, but CS categorized 47 LBC ASCUS as negative. From the morphological parameters nuclear enlargement and coarse chromatin were regarded as ASCUS. From 68 ASCUS by LBC, 36 were HC2 positive for high risk HPV (hr-HPV) : ten of them with biopsy proven lesion. From 42 CS ASCUS, 23 were hr-HPV positive, but only 7 with histological lesion. Conclusion: our results reinforced the hypothesis that ASCUS is poorly reproducible by morphological examination by CS or LBC preparations. To add HC2 as adjunct method to ASCUS cytology can improve the routine diagnosed of the uncertain atypies

Investigating nurses’ quality of life and work-life balance statuses in Singapore

tertiary hospital in Singapore. Background: Nurses’ quality of life can directly and indirectly impact patients’ safety and quality of care. Therefore, identifying key factors that influence nurses’ quality of life is essential in the healthcare delivery system. Methods: A descriptive quantitative study design was adopted, and validated questionnaires were used. Data were collected in a period of 3 months (March to May 2014) at a 600-bed tertiary hospital in Singapore. One thousand and forty nurses participated in the study. Results: Social support and sense of coherence were found to be significant predictors for high quality of life in all domains. Most nurses in this study spent more time on work than their private lives. However, there was no significant difference in job satisfaction among the four groups of nurses’ proportions of percentages of actual time spent on work and private life. Conclusions: Cultivating social support from family, friends/colleagues and supervisors can help an individual cope with stress and enhance a nurse’s quality of life. Implications for nursing policy and practice: Even though nurses who spent more time at work were still satisfied with their job, they might need to be aware of their physical health and work environment. Nursing policy related to nurses’ physical health and environment should be established. Health promotion programmes such as physical exercise and mindfulness interventions should be conducted to promote nurses’ well-being and healthy workplace environments to enhance nurses’ quality of life

Screening for cervical Cancer in high-risk populations: DNA pap test or hybrid capture II test alone?

This study was designed to evaluate whether Hybrid Capture II (HC2) test alone refer women to colposcopy as appropriately as DNA Papanicolaou (Pap) test, in the context of a high-risk group of women using the recently validated DNACitoliq LBC system. Women with suspected cervical disease were included in this crosssectional study at a tertiary center in São Paulo, Brazil, for further workup. All women had cervical material collected for LBC and HC2 for high-risk human papillomavirus (hrHPV)-DNA test. Irrespective of cytology and HC2 results, colposcopy, and cervical biopsy when applicable, was systematically performed. All tests were performed blindly. Sensitivity, specificity, positive and negative predictive values, and overall accuracy of both methods were computed in relation to histology. A total of 1,080 women were included: 36.4% (393/1080) had ACUS+, 10.2% (110/1080) were high-grade squamous intraepithelial lesions (HSIL) or cancer. Mean age was 33.5 years. All women underwent colposcopy, and cervical biopsies were performed in 38.4% (415/1080): 33% (137/415) of the biopsies were negative, 14.4% (155/415) were low-grade squamous intraepithelial lesions (LSIL), 10.7% (116/415) were HSIL, and 0.6% (7/415) were cancer. HC2 sensitivity to diagnose biopsy-proven HSIL was 100%. Because all HSIL cases had a positive HC2 test, sensitivity could not be improved by adding LBC. Specificity and positive and negative predictive values of DNA Pap were not significantly different from HC2 test alone when considering LSIL+ histology as ‘‘gold standard’’ and HSIL+ histology. As a screening strategy for women with high-risk for cervical cancer, DNA Pap test does not seem to add substantially to HC2 alone in terms of appropriately referring to colposcopy