Diachronic Topics in New High German Poetry

Statistical topic models are increasingly and popularly used by Digital Humanities scholars to perform distant reading tasks on literary data. It allows us to estimate what people talk about. Especially Latent Dirichlet Allocation (LDA) has shown its usefulness, as it is unsupervised, robust, easy to use, scalable, and it offers interpretable results. In a preliminary study, we apply LDA to a corpus of New High German poetry (textgrid, with 51k poems, 8m token), and use the distribution of topics over documents for a classification of poems into time periods and for authorship attribution

Composite vertices that lead to soft form factors

The momentum-space cut-off parameter $\Lambda$ of hadronic vertex functions is studied in this paper. We use a composite model where we can measure the contributions of intermediate particle propagations to $\Lambda$. We show that in many cases a composite vertex function has a much smaller cut-off than its constituent vertices, particularly when light constituents such as pions are present in the intermediate state. This suggests that composite meson-baryon-baryon vertex functions are rather soft, i.e., they have \Lambda considerably less than 1 GeV. We discuss the origin of this softening of form factors as well as the implications of our findings on the modeling of nuclear reactions.Comment: REVTex, 19 pages, 5 figs(to be provided on request

HIV envelope tail truncation confers resistance to SERINC5 restriction

SERINCs and IFITMs are potent lentiviral restriction factors that inhibit infection by blocking viral entry into cells. Specifically, SERINCs inhibit viral fusion by targeting the envelope glycoprotein (Env) by a mechanism that remains incompletely understood. Here, we report that truncation of the Env cytoplasmic tail (CT) of HIV-1 and HIV-2 confers complete resistance to SERINC and IFITM restriction. Notably, while the EnvCT of HIV-1 is necessary for viral replication in T cells, HIV-2 does not require the EnvCT. Our data suggest a mechanism by which human lentiviruses can evade restriction that is mediated by the EnvCT but reveal key differences in the likely fitness cost imposed by this on pandemic HIV-1 and nonpandemic HIV-2

Determinants of adolescent fertility in Ethiopia

Background: Worldwide, adolescents suffer from a disproportionate share of reproductive health problem. Throughout the world, over 14 million adolescents aged 15-19 years give birth annually. The purpose of this study was to assess the level and identify proximate and other determinants of adolescent fertility in Ethiopia.Methods: Raw data collected from all part of the country using stratified cluster sampling method by the Ethiopian Demographic Health Survey 2005 (EDHS-2005) was used. After the data for adolescents aged from 15 to 19 years were extracted from the large data set, Multivariate logistic regression model was applied to identify sociodemographic and economic determinants whereas Bongaarts model was used to determine proximate determinants fertility.Results: Of the 3,266 adolescent women, 443 (13.6%) had given birth at least once prior to the survey and 133 (4.1%) were pregnant. Of the 443 adolescents who had at least given birth, the majority (72.7%) had one child while about a quarter (23.2%) had 2 live births and the rest 1.0% gave four live births with a mean number of child ever born of 1.33±0.6. The major factors associated with adolescent fertility were age, educational status, place of residence, employment, marriage, contraceptive use and postpartum infecundability. The odds for increased adolescent fertility was significantly higher in early adolescents (AOR=7.6; 95% CI=6.0 to 9.9), had lower education (AOR=6.7; 95%CI=4.1 to10.9), among rural teens (AOR=3.6; 95%CI=1.9 to 6.9) and currently not working (AOR=1.7; 95%CI= 1.3 to 2.2) than their counterparts. The observed fertility rate of 0.52 children per woman obtained from Bongaarts model of fertility indicated about 1.98 births per woman were averted due to non-marriage, delayed marriage, contraceptive use and postpartum infecundability.Conclusion: Since adolescent fertility is felt to be a problem, concerted efforts are needed to empower adolescents to fight early marriage, promote education and encourage the utilization of family planning targeting the rural teenagers. [Ethiop. J. Health Dev. 2010;24(1):30-38

The Role of Δ(1232)\Delta(1232) in Two-pion Exchange Three-nucleon Potential

In this paper we have studied the two-pion exchange three-nucleon potential $(2\pi E-3NP)$ using an approximate $SU(2) \times SU(2)$ chiral symmetry of the strong interaction. The off-shell pion-nucleon scattering amplitudes obtained from the Weinberg Lagangian are supplemented with contributions from the well-known $\sigma$-term and the $\Delta(1232)$ exchange. It is the role of the $\Delta$-resonance in $2\pi E-3NP$, which we have investigated in detail in the framework of the Lagrangian field theory. The $\Delta$-contribution is quite appreciable and, more significantly, it is dependent on a parameter Z which is arbitrary but has the empirical bounds $|Z| \leq 1/2$. We find that the $\Delta$-contribution to the important parameters of the $2\pi E-3NP$ depends on the choice of a value for Z, although the correction to the binding energy of triton is not expected to be very sensitive to the variation of Z within its bounds.Comment: 14 pages, LaTe

Enhancing properties of iron and manganese ores as oxygen carriers for chemical looping processes by dry impregnation

The use of naturally occurring ores as oxygen carriers in CLC processes is attractive because of their relative abundance and low cost. Unfortunately, they typically exhibit lower reactivity and lack the mechanical robustness required, when compared to synthetically produced carriers. Impregnation is a suitable method for enhancing both the reactivity and durability of natural ores when used as oxygen carriers for CLC systems. This investigation uses impregnation to improve the chemical and mechanical properties of a Brazilian manganese ore and a Canadian iron ore. The manganese ore was impregnated with Fe2O3 and the iron ore was impregnated with Mn2O3 with the goal of forming a combined Fe/Mn oxygen carrier. The impregnated ore’s physical characteristics were assessed by SEM, BET and XRD analysis. Measurements of the attrition resistance and crushing strength were used to investigate the mechanical robustness of the oxygen carriers. The impregnated ore’s mechanical and physical properties were clearly enhanced by the impregnation method, with boosts in crushing strength of 11–26% and attrition resistance of 37–31% for the impregnated iron and manganese ores, respectively. Both the unmodified and impregnated ore’s reactivity, for the conversion of gaseous fuel (CH4 and syngas) and gaseous oxygen release (CLOU potential) were investigated using a bench-scale quartz fluidised-bed reactor. The impregnated iron ore exhibited a greater degree of syngas conversion compared to the other samples examined. Iron ore based oxygen carrier’s syngas conversion increases with the number of oxidation and reduction cycles performed. The impregnated iron ore exhibited gaseous oxygen release over extended periods in an inert atmosphere and remained at a constant 0.2% O2 concentration by volume at the end of this inert period. This oxygen release would help ensure the efficient use of solid fuels. The impregnated iron ore’s reactivity for CH4 conversion was similar to the reactivity of its unmodified counterpart. The unmodified manganese ore converted CH4 to the greatest extent of all the samples tested here, while the impregnated manganese ore exhibited a decrease in reactivity with respect to syngas and CH4 conversion.EPSR