Monte Carlo Markov Chain parameter estimation in semi-analytic models of galaxy formation

We present a statistical exploration of the parameter space of the De Lucia and Blaizot version of the Munich semi-analytic (SA) model built upon the Millennium dark matter simulation. This is achieved by applying a Monte Carlo Markov Chain method to constrain the six free parameters that define the stellar and black hole mass functions at redshift zero. The model is tested against three different observational data sets, including the galaxy K-band luminosity function, B - V colours and the black hole-bulge mass relation, separately and combined, to obtain mean values, confidence limits and likelihood contours for the best-fitting model. Using each observational data set independently, we discuss how the SA model parameters affect each galaxy property and find that there are strong correlations between them. We analyse to what extent these are simply reflections of the observational constraints, or whether they can lead to improved understandings of the physics of galaxy formation. When all the observations are combined, we find reasonable agreement between the majority of the previously published parameter values and our confidence limits. However, the need to suppress dwarf galaxy formation requires the strength of the supernova feedback to be significantly higher in our best-fitting solution than in previous work. To balance this, we require the feedback to become ineffective in haloes of lower mass than before, so as to permit the formation of sufficient high-luminosity galaxies: unfortunately, this leads to an excess of galaxies around L*. Although the best fit is formally consistent with the data, there is no region of parameter space that reproduces the shape of galaxy luminosity function across the whole magnitude range. For our best fit, we present the model predictions for the bJ-band luminosity and stellar mass functions. We find a systematic disagreement between the observed mass function and the predictions from the K-band constraint, which we explain in light of recent works that suggest uncertainties of up to 0.3 dex in the mass determination from stellar population synthesis models. We discuss modifications to the SA model that might simultaneously improve the fit to the observed mass function and reduce the reliance on excessive supernova feedback in small haloes

Butterfly abundance in a warming climate: patterns in space and time are not congruent

We present a model of butterfly abundance on transects in England. The model indicates a significant role for climate, but the direction of association is counter to expectation: butterfly population density is higher on sites with a cooler climate. However, the effect is highly heterogeneous, with one in five species displaying a net positive association. We use this model to project the population-level effects of climate warming for the year 2080, using a medium emissions scenario. The results suggest that most populations and species will decline markedly, but that the total number of butterflies will increase as communities become dominated by a few common species. In particular, Maniola jurtina is predicted to make up nearly half of all butterflies on UK Butterfly Monitoring Scheme (UKBMS) transects by 2080. These results contradict the accepted wisdom that most insect populations will grow as the climate becomes warmer. Indeed, our predictions contrast strongly with those derived from inter-annual variation in abundance, emphasizing that we lack a mechanistic understanding about the factors driving butterfly population dynamics over large spatial and temporal scales. Our study underscores the difficulty of predicting future population trends and reveals the naivety of simple space-for-time substitutions, which our projections share with species distribution modelling

Standardization and application of microsatellite markers for variety identification in tomato and wheat

The present study is part of a EU project that aims to demonstrate the technical viability of STMS markers for variety identification. As examples two important European crop species, tomato and wheat were chosen. Initially, about 30-40 STMS markers were used to identify a set of 20 good markers per crop and to standardise the methodology and the interpretation of the results in different laboratories. Several systems were used for the detection of STMS polymorphisms. The selected STMS markers are being tested on 500 varieties of each species and databases are being constructed. The first comparisons of data generated by the different laboratories revealed a high degree of agreement. The causes of discrepancies between duplicate samples analysed in different laboratories and precautions to prevent them, are discussed

A variety of Levitrons: A review

After a brief history and critique of some older instruments, several new Levitron geometries are described. As a result of their greater stability these devices can be used as analogues of a number of phenomena and applications, including magnetic resonance techniques, atom traps and accelerator rings. In particular, the notion of the spinning magnet (or spignet) in a linear trap is similar to the mechanism underpinning the confinement of antihydrogen in a magnetic minimum trap, as achieved in experiments at CERN

Nuclear symmetry energy and the r-mode instability of neutron stars

We analyze the role of the symmetry energy slope parameter $L$ on the {\it r}-mode instability of neutron stars. Our study is performed using both microscopic and phenomenological approaches of the nuclear equation of state. The microscopic ones include the Brueckner--Hartree--Fock approximation, the well known variational equation of state of Akmal, Pandharipande and Ravenhall, and a parametrization of recent Auxiliary Field Diffusion Monte Carlo calculations. For the phenomenological approaches, we use several Skyrme forces and relativisic mean field models. Our results show that the {\it r}-mode instability region is smaller for those models which give larger values of $L$. The reason is that both bulk ($\xi$) and shear ($\eta$) viscosities increase with $L$ and, therefore, the damping of the mode is more efficient for the models with larger $L$. We show also that the dependence of both viscosities on $L$ can be described at each density by simple power-laws of the type $\xi=A_{\xi}L^{B_\xi}$ and $\eta=A_{\eta}L^{B_\eta}$. Using the measured spin frequency and the estimated core temperature of the pulsar in the low-mass X-ray binary 4U 1608-52, we conclude that observational data seem to favor values of $L$ larger than $\sim 50$ MeV if this object is assumed to be outside the instability region, its radius is in the range $11.5-12$($11.5-13$) km, and its mass $1.4M_\odot$($2M_\odot$). Outside this range it is not possible to draw any conclusion on $L$ from this pulsar.Comment: 10 pages, 6 figures. Version published in Physical Review

The Nigeria Teachers Social Studies Training Curriculum and Sustainable Development Goals: A Content Analysis

The concept of sustainable development has become a widely used construct that is incorporated into virtually all disciplines and discourses. The implementation and achievement of sustainable development goals in the management of our environmental resources cannot be realised without education especially at a formal levels. Teacher training institutions - (college of education and faculty of education in universities) are expected through their courses to engage and create awareness of sustainability issues using their training programmes. This paper therefore presents a content analysis of sustainability themes and concepts in the College of Education Social Studies curriculum in Nigeria.  This is with the ultimate goal of exploring how any noticed gaps that could inhibit the promotion of education for sustainable development through teacher training can be filled, so that the post 2015 sustainable development goals could be better achieved

China Maritime Report No. 6: Djibouti: China\u27s First Overseas Strategic Strongpoint

This China Maritime Report on Djibouti is the first in a series of case studies on China’s “overseas strategic strongpoints” (海外战略支点). The strategic strongpoint concept has no formal definition, but is used by People’s Republic of China (PRC) officials and analysts to describe foreign ports with special strategic and economic value that host terminals and commercial zones operated by Chinese firms.https://digital-commons.usnwc.edu/cmsi-maritime-reports/1005/thumbnail.jp

China Maritime Report No. 7: Gwadar: China\u27s Potential Strategic Strongpoint in Pakistan

This China Maritime Report on Gwadar is the second in a series of case studies on China’s Indian Ocean “strategic strongpoints” (战略支点). People’s Republic of China (PRC) officials, military officers, and civilian analysts use the strategic strongpoint concept to describe certain strategically valuable foreign ports with terminals and commercial zones owned and operated by Chinese firms.https://digital-commons.usnwc.edu/cmsi-maritime-reports/1006/thumbnail.jp

Improving randomness characterization through Bayesian model selection

Nowadays random number generation plays an essential role in technology with important applications in areas ranging from cryptography, which lies at the core of current communication protocols, to Monte Carlo methods, and other probabilistic algorithms. In this context, a crucial scientific endeavour is to develop effective methods that allow the characterization of random number generators. However, commonly employed methods either lack formality (e.g. the NIST test suite), or are inapplicable in principle (e.g. the characterization derived from the Algorithmic Theory of Information (ATI)). In this letter we present a novel method based on Bayesian model selection, which is both rigorous and effective, for characterizing randomness in a bit sequence. We derive analytic expressions for a model's likelihood which is then used to compute its posterior probability distribution. Our method proves to be more rigorous than NIST's suite and the Borel-Normality criterion and its implementation is straightforward. We have applied our method to an experimental device based on the process of spontaneous parametric downconversion, implemented in our laboratory, to confirm that it behaves as a genuine quantum random number generator (QRNG). As our approach relies on Bayesian inference, which entails model generalizability, our scheme transcends individual sequence analysis, leading to a characterization of the source of the random sequences itself.Comment: 25 page

Chiral model approach to quark matter nucleation in neutron stars

The nucleation process of quark matter in both cold and hot dense hadronic matter is investigated using a chiral approach to describe the quark phase. We use the Nambu-Jona-Lasinio and the Chromo Dielectric models to describe the deconfined phase and the non-linear Walecka model for the hadronic one. The effect of hyperons on the transition phase between hadronic and quark matter is studied. The consequences of the nucleation process for neutron star physics are outlined