Min-oscillations in Escherichia coli induced by interactions of membrane-bound proteins

During division it is of primary importance for a cell to correctly determine the site of cleavage. The bacterium Escherichia coli divides in the center, producing two daughter cells of equal size. Selection of the center as the correct division site is in part achieved by the Min-proteins. They oscillate between the two cell poles and thereby prevent division at these locations. Here, a phenomenological description for these oscillations is presented, where lateral interactions between proteins on the cell membrane play a key role. Solutions to the dynamic equations are compared to experimental findings. In particular, the temporal period of the oscillations is measured as a function of the cell length and found to be compatible with the theoretical prediction.Comment: 17 pages, 5 figures. Submitted to Physical Biolog

Modification of cosmic-ray energy spectra by stochastic acceleration

Context: Typical space plasmas contain spatially and temporally variable turbulent electromagnetic fields. Understanding the transport of energetic particles and the acceleration mechanisms for charged particles is an important goal of today's astroparticle physics. Aims: To understand the acceleration mechanisms at the particle source, subsequent effects have to be known. Therefore, the modification of a particle energy distribution, due to stochastic acceleration, needs to be investigated. Methods: The diffusion in momentum space was investigated by using both a Monte-Carlo simulation code and by analytically solving the momentum-diffusion equation. For simplicity, the turbulence was assumed to consist of one-dimensional Alfven waves. Results: Using both methods, it is shown that, on average, all particles with velocities comparable to the Alfven speeds are accelerated. This influences the energy distribution by significantly increasing the energy spectral index. Conclusions: Because of electromagnetic turbulence, a particle energy spectrum measured at Earth can drastically deviate from its initial spectrum. However, for particles with velocities significantly above the Alfven speed, the effect becomes negligible.Comment: 10 pages, 6 figures, accepted for publication in Astronomy & Astrophysic

Universality in escape from a modulated potential well

We show that the rate of activated escape $W$ from a periodically modulated potential displays scaling behavior versus modulation amplitude $A$. For adiabatic modulation of an optically trapped Brownian particle, measurements yield $\ln W\propto (A_{\rm c} - A)^{\mu}$ with $\mu = 1.5$. The theory gives $\mu=3/2$ in the adiabatic limit and predicts a crossover to $\mu=2$ scaling as $A$ approaches the bifurcation point where the metastable state disappears.Comment: 4 pages, 3 figure

Ab-initio shell model with a core

We construct effective 2- and 3-body Hamiltonians for the p-shell by performing 12\hbar\Omega ab initio no-core shell model (NCSM) calculations for A=6 and 7 nuclei and explicitly projecting the many-body Hamiltonians onto the 0\hbar\Omega space. We then separate these effective Hamiltonians into 0-, 1- and 2-body contributions (also 3-body for A=7) and analyze the systematic behavior of these different parts as a function of the mass number A and size of the NCSM basis space. The role of effective 3- and higher-body interactions for A>6 is investigated and discussed

Marginal benefit incidence of public health spending: evidence from Indonesian sub-national data

We examine the marginal effects of decentralized public health spending by incorporating estimates of behavioural responses to changes in public health spending through benefit incidence analysis. The analysis is based on a panel dataset of 207 Indonesian districts over a 4-year period from 2001 to 2004. We show that district-level public health spending is largely driven by central government transfers, with an elasticity of public health spending with respect to district revenues of around 0.9. We find a positive effect of public health spending on utilization of outpatient care in the public sector for the poorest two quartiles. We find no evidence that public expenditures crowd oututilization of private services or household health spending. Our analysis suggests that increased public health spending improves targeting to the poor, as behavioural changes in public health care utilization are pro-poor. Nonetheless, most of the benefits of the additional spending accrued to existing users of services, as initial utilization shares outweigh the behavioural responses

Models of the fate of glucosinolates in Brassicaceae from processing to digestion

Abstract Glucosinolates are secondary metabolites of Brassica vegetables. Glucosinolates are not bioactive themselves, but their hydrolysis products isothiocyanates have been associated with health benefits. The concentrations of glucosinolates and their break down products are strongly affected by processing of the vegetables, but are also affected by digestion conditions. During thermal treatment of Brassicaceae, such as domestic cooking, different mechanisms affecting the content of glucosinolates can take place and were modelled in the present study: Lysis of plant cells and compartments, leaching of glucosinolates into the cooking water and thermal degradation of glucosinolates in both the intact vegetable tissue and in the cooking water. These mechanisms were described mathematically and the model parameters for broccoli, Brussels sprouts, red cabbage and white cabbage were estimated based on experimental results. Differences between the thermostability of the same glucosinolates originating from different Brassicaceae could be detected, as well as differences between the thermostability of the same glucosinolates in the vegetable matrix compared to that in cooking water. This mathematical model and the estimated parameters can be used to simulate the different glucosinolate contents in prepared foods considering the processing method. This should be a useful tool in food research and industry to make predictions about the nutritional quality of foods and to optimize their health related quality attributes. In broccoli, the glucosinolate glucoraphanin and its breakdown products were further studied in an in vitro digestion study and an in vivo chewing study with five subjects. Upon cell damage, e.g. during chewing, the glucosinolate glucoraphanin is hydrolyzed by the endogenous enzyme myrosinase and, depending on the environmental conditions, sulforaphane or sulforaphane nitrile are produced. The effect of steaming time (raw or steamed for 1, 2 or 3 min) and meal composition (with and without addition of protein (bovine serum albumin or lipid (olive oil)) on the conversion of glucoraphanin were studied in an in vitro digestion model and the bioaccessibility of released breakdown products investigated. The main formation of sulforaphane and sulforaphane nitrile from glucoraphanin occurred during the in vitro oral phase. The content of glucoraphanin, sulforaphane and sulforaphane nitrile did not degrade after digestion. Sulforaphane concentrations were up to 10-times higher in raw and 1-min steamed broccoli samples after the digestion compared to broccoli that was steamed 2 or 3 min. The addition of bovine serum albumin and olive oil had no influence on the formation and bioaccessibility of sulforaphane or sulforaphane nitrile. Meal preparation seems to have a much more pronounced effect on SF formation and bioaccessibility compared to meal composition. In an in vitro study the effect of chewing time (11 s, 22 s, 30 s and 40 s) on differently steamed broccoli ( raw or steamed for 0.5-min, 1-min 2-min and 3-min) was studied. Chewing time influenced the amount of hydrolysis of glucoraphanin in raw and short steamed broccoli that contains active myrosinase (raw, 0.5-min and 1-min steamed), but not in broccoli that had been steamed longer. Steaming time showed to influence the oral hydrolysis of glucoraphanin. Both chewing time and steaming time influence the enzymatic breakdown of glucoraphanin in the mouth. Longer chewing times of raw and short steamed broccoli (0.5-min and 1-min), which contains active myrosinase, lead to more hydrolysis.</p

Satisfying the Einstein-Podolsky-Rosen criterion with massive particles

In 1935, Einstein, Podolsky and Rosen (EPR) questioned the completeness of quantum mechanics by devising a quantum state of two massive particles with maximally correlated space and momentum coordinates. The EPR criterion qualifies such continuous-variable entangled states, where a measurement of one subsystem seemingly allows for a prediction of the second subsystem beyond the Heisenberg uncertainty relation. Up to now, continuous-variable EPR correlations have only been created with photons, while the demonstration of such strongly correlated states with massive particles is still outstanding. Here, we report on the creation of an EPR-correlated two-mode squeezed state in an ultracold atomic ensemble. The state shows an EPR entanglement parameter of 0.18(3), which is 2.4 standard deviations below the threshold 1/4 of the EPR criterion. We also present a full tomographic reconstruction of the underlying many-particle quantum state. The state presents a resource for tests of quantum nonlocality and a wide variety of applications in the field of continuous-variable quantum information and metrology.Comment: 8 pages, 7 figure

Effective operators from exact many-body renormalization

We construct effective two-body Hamiltonians and E2 operators for the p-shell by performing $16\hbar\Omega$ ab initio no-core shell model (NCSM) calculations for A=5 and A=6 nuclei and explicitly projecting the many-body Hamiltonians and E2 operator onto the $0\hbar\Omega$ space. We then separate the effective E2 operator into one-body and two-body contributions employing the two-body valence cluster approximation. We analyze the convergence of proton and neutron valence one-body contributions with increasing model space size and explore the role of valence two-body contributions. We show that the constructed effective E2 operator can be parametrized in terms of one-body effective charges giving a good estimate of the NCSM result for heavier p-shell nuclei.Comment: 9 pages, 8 figure

From the Economic Union to the Harmonisation of Higher Education in the BRICS Countries: The Experience of RUDN University

Since 2009 when Brazil, Russia, India, and China (South Africa since 2011) joined in the international organisation aimed at the economic development of the countries, and gain financial stability, the relations between the countries too boosted via political and cultural cooperation. The new economic, political and social environment has a high demand for competent specialists ready to work in various national agendas and interrelated frameworks of the BRICS. In this context, it is argued that professional training in the countries under discussion should be correlated as it provides grounds for quality assurance in education that contributes to the nations’ sustainable development, safety, and human rights provision. This situation determines the topicality of the issue. The objective of this research is to study the higher educational environment in the BRICS countries and to compare some aspects of professional training. In doing so, the study aims to present the experience of RUDN University as one of the BRICS university network members. The hypothesis states that the harmonisation of higher education systems within regional organisations can contribute to the enhancement of both international standards and individual learning paths, thus fostering youth rights for education in line with quality standards and individual preferences. To accomplish the objectives of the study, it uses the following methods - the review of the current research, formal document and online resources on higher education in the BRICS countries; the survey of the undergraduates, graduates, and postgraduates on their motivation to academic mobility, and collaboration in the frameworks of BRICS higher education. The data has been analysed employing the methods of statistical processing, qualitative and quantitative methods. The findings of the current research include the outcomes and findings on the harmonisation of higher education in the frameworks of BRICS higher education. The study will contribute to further development of BRICS countries education and the harmonisation of higher education. &nbsp