Angular Correlations in Internal Pair Conversion of Aligned Heavy Nuclei

We calculate the spatial correlation of electrons and positrons emitted by internal pair conversion of Coulomb excited nuclei in heavy ion collisions. The alignment or polarization of the nucleus results in an anisotropic emission of the electron-positron pairs which is closely related to the anisotropic emission of $\gamma$-rays. However, the angular correlation in the case of internal pair conversion exhibits diverse patterns. This might be relevant when investigating atomic processes in heavy-ion collisions performed at the Coulomb barrier.Comment: 27 pages + 6 eps figures, uses revtex.sty and epsf.sty, tar-compressed and uuencoded with uufile

On the Geometry of Supersymmetric Quantum Mechanical Systems

We consider some simple examples of supersymmetric quantum mechanical systems and explore their possible geometric interpretation with the help of geometric aspects of real Clifford algebras. This leads to natural extensions of the considered systems to higher dimensions and more complicated potentials.Comment: 18 page

The speciation of the proteome

<p>Abstract</p> <p>Introduction</p> <p>In proteomics a paradox situation developed in the last years. At one side it is basic knowledge that proteins are post-translationally modified and occur in different isoforms. At the other side the protein expression concept disclaims post-translational modifications by connecting protein names directly with function.</p> <p>Discussion</p> <p>Optimal proteome coverage is today reached by bottom-up liquid chromatography/mass spectrometry. But quantification at the peptide level in shotgun or bottom-up approaches by liquid chromatography and mass spectrometry is completely ignoring that a special peptide may exist in an unmodified form and in several-fold modified forms. The acceptance of the protein species concept is a basic prerequisite for meaningful quantitative analyses in functional proteomics. In discovery approaches only top-down analyses, separating the protein species before digestion, identification and quantification by two-dimensional gel electrophoresis or protein liquid chromatography, allow the correlation between changes of a biological situation and function.</p> <p>Conclusion</p> <p>To obtain biological relevant information kinetics and systems biology have to be performed at the protein species level, which is the major challenge in proteomics today.</p

Identifying children with Cystic Fibrosis in population-scale routinely collected data in Wales

IntroductionThe challenges in identifying a cohort of people with a rare condition can be addressed by routinely collected, population-scale electronic health record (EHR) data, which provide large volumes of data at a national level. This paper describes the challenges of accurately identifying a cohort of children with Cystic Fibrosis (CF) using EHR and their validation against the UK CF Registry.ObjectivesTo establish a proof of principle and provide insight into the merits of linked data in CF research; to identify the benefits of access to multiple data sources, in particular the UK CF Registry data, and to demonstrate the opportunity it represents as a resource for future CF research.MethodsThree EHR data sources were used to identify children with CF born in Wales between 1st January 1998 and 31st August 2015 within the Secure Anonymised Information Linkage (SAIL) Databank. The UK CF Registry was later acquired by SAIL and linked to the EHR cohort to validate the cases and explore the reasons for misclassifications.ResultsWe identified 352 children with CF in the three EHR data sources. This was greater than expected based on historical incidence rates in Wales. Subsequent validation using the UK CF Registry found that 257 (73%) of these were true cases. Approximately 98.7% (156/158) of individuals identified as CF cases in all three EHR data sources were confirmed as true cases; but this was only the case for 19.8% (20/101) of all those identified in just a single data source.ConclusionIdentifying health conditions in EHR data can be challenging, so data quality assurance and validation is important or the merit of the research is undermined. This retrospective review identifies some of the challenges in identifying CF cases and demonstrates the benefits of linking cases across multiple data sources to improve quality

On a new definition of quantum entropy

It is proved here that, as a consequence of the unitary quantum evolution, the expectation value of a properly defined quantum entropy operator (as opposed to the non-evolving von Neumann entropy) can only increase during non adiabatic transformations and remains constant during adiabatic ones. Thus Clausius formulation of the second law is established as a theorem in quantum mechanics, in a way that is equivalent to the previously established formulation in terms of minimal work principle [A. E. Allahverdyan and T. M. Nieuwenhuizen, Phys. Rev. E 71, 046107 (2005)]. The corresponding Quantum Mechanical Principle of Entropy Increase is then illustrated with an exactly solvable example, namely the driven harmonic oscillator. Attention is paid to both microcanonical and canonical initial condition. The results are compared to their classical counterparts.Comment: 4 pages, 3 figure

Inlet conditions for large eddy simulation of gas-turbine swirl injectors

Copyright © 2008 American Institute of Aeronautics and AstronauticsIn this paper, we present a novel technique for generating swirl inlets for large eddy simulation. The velocity a short distance downstream of the inlet to the main domain is sampled and the flow velocity data are reintroduced back into the domain inlet, creating an inlet section integrated into the main domain in which turbulence can develop. Additionally, variable artificial body forces and velocity corrections are imposed in this inlet section, with feedback control to force the flow toward desired swirl, mean, and turbulent profiles. The method was applied to flow in an axisymmetric sudden expansion, with and without swirl at the inlet, and compared against experimental and literature large eddy simulation data and against similar results in the literature. The method generates excellent results for this case and is elegant and straightforward to implement

Membrance interface evaluations for underwater mass spectrometers.

A component that has enabled the development of underwater mass spectrometry is a mechanically supported membrane interface probe. Our two research groups have used metallic porous frits that support polydimethyl siloxane (PDMS) membranes embedded in a heated membrane probe assembly, allowing the deployment of the underwater membrane introduction mass spectrometer (MIMS) instruments to ocean depths of 2000 meters. The fabrication of such frits has consisted of shaping larger Hastalloy C porous frits to the size required to support a PDMS capillary of 0.64 mm ID and 1.19 mm OD using a diamond‐coated wheel and Dremel tool. This procedure is time‐consuming and cumbersome, and the porosity of the final frits is likely not reproducible. To facilitate the fabrication of the membrane assembly, we report on the use of new porous metallic structures. Frits with diameters of approximately 3.0 mm (1/8”) and known porosities (48.3 % and 32.5%) were produced by the Fraunhofer Institute in Dresden, Germany, using powder metallurgical processes. We used these frits to fabricate new membrane interface assemblies. Using a new custom‐heated membrane probe with the new porous frits, we performed calibrations relating dissolved methane concentrations to mass spectrometer response (m/z 15) using linear least‐squares fitting procedures. Both the limit of detection (methane concentration in the tens of nanomolars) and the sensitivity (on the order of 10‐1 pico‐amps/nanomole of methane) were found to be comparable with those obtained with the previously fabricated Hastelloy C frits. The calibration parameters for the new assembly were also found to be a function of the flow rate, temperature, and sample hydrostatic pressure

A diagnostic procedure for applying the social-ecological systems framework in diverse cases

The framework for analyzing sustainability of social-ecological systems (SES) framework of Elinor Ostrom is a multitier collection of concepts and variables that have proven to be relevant for understanding outcomes in diverse SES. The first tier of this framework includes the concepts resource system (RS) and resource units (RU), which are then further characterized through lower tier variables such as clarity of system boundaries and mobility. The long-term goal of framework development is to derive conclusions about which combinations of variables explain outcomes across diverse types of SES. This will only be possible if the concepts and variables of the framework can be made operational unambiguously for the different types of SES, which, however, remains a challenge. Reasons for this are that case studies examine other types of RS than those for which the framework has been developed or consider RS for which different actors obtain different kinds of RU. We explore these difficulties and relate them to antecedent work on common-pool resources and public goods. We propose a diagnostic procedure which resolves some of these difficulties by establishing a sequence of questions that facilitate the step-wise and unambiguous application of the SES framework to a given case. The questions relate to the actors benefiting from the SES, the collective goods involved in the generation of those benefits, and the action situations in which the collective goods are provided and appropriated. We illustrate the diagnostic procedure for four case studies in the context of irrigated agriculture in New Mexico, common property meadows in the Swiss Alps, recreational fishery in Germany, and energy regions in Austria. We conclude that the current SES framework has limitations when applied to complex, multiuse SES, because it does not sufficiently capture the actor interdependencies introduced through RS and RU characteristics and dynamics

Toxoplasma effectors targeting host signaling and transcription

Early electron microscopy studies revealed the elaborate cellular features that define the unique adaptations of apicomplexan parasites. Among these were bulbous rhoptry (ROP) organelles and small, dense granules (GRAs), both of which are secreted during invasion of host cells. These early morphological studies were followed by the exploration of the cellular contents of these secretory organelles, revealing them to be comprised of highly divergent protein families with few conserved domains or predicted functions. In parallel, studies on host-pathogen interactions identified many host signaling pathways that were mysteriously altered by infection. It was only with the advent of forward and reverse genetic strategies that the connections between individual parasite effectors and the specific host pathways that they targeted finally became clear. The current repertoire of parasite effectors includes ROP kinases and pseudokinases that are secreted during invasion and that block host immune pathways. Similarly, many secretory GRA proteins alter host gene expression by activating host transcription factors, through modification of chromatin, or by inducing small noncoding RNAs. These effectors highlight novel mechanisms by whichhas learned to harness host signaling to favor intracellular survival and will guide future studies designed to uncover the additional complexity of this intricate host-pathogen interaction

Principle of Maximum Entropy Applied to Rayleigh-B\'enard Convection

A statistical-mechanical investigation is performed on Rayleigh-B\'enard convection of a dilute classical gas starting from the Boltzmann equation. We first present a microscopic derivation of basic hydrodynamic equations and an expression of entropy appropriate for the convection. This includes an alternative justification for the Oberbeck-Boussinesq approximation. We then calculate entropy change through the convective transition choosing mechanical quantities as independent variables. Above the critical Rayleigh number, the system is found to evolve from the heat-conducting uniform state towards the convective roll state with monotonic increase of entropy on the average. Thus, the principle of maximum entropy proposed for nonequilibrium steady states in a preceding paper is indeed obeyed in this prototype example. The principle also provides a natural explanation for the enhancement of the Nusselt number in convection.Comment: 13 pages, 4 figures; typos corrected; Eq. (66a) corrected to remove a double counting for $k_{\perp}=0$; Figs. 1-4 replace