On the Density of Coprime m-tuples over Holomorphy Rings

Let $\mathbb F_q$ be a finite field, $F/\mathbb F_q$ be a function field of genus $g$ having full constant field $\mathbb F_q$, $\mathcal S$ a set of places of $F$ and $H$ the holomorphy ring of $\mathcal S$. In this paper we compute the density of coprime $m$-tuples of elements of $H$. As a side result, we obtain that whenever the complement of $\mathcal S$ is finite, the computation of the density can be reduced to the computation of the $L$-polynomial of the function field. In the rational function field case, classical results for the density of coprime $m$-tuples of polynomials are obtained as corollaries.Comment: To appear in International Journal of Number Theor

The Steady State Chlorophyll a Fluorescence Exhibits in Vivo an Optimum as a Function of Light Intensity which Reflects the Physiological State of the Plant

Modulated (690 and 730 nm), as well as direct chlorophyll (Chl) a fluorescence and changes in the concentration of the oxidized P700 were measured under steady state conditions in leaves of higher plants adapted to different light intensities. All the leaf samples exhibit an optimum curve of steady state fluorescence yield (Fs) versus the light intensity but its position with respect to light intensity varies considerably from one species to another or from one sample to other even in the same plant or within the same leaf sample. However, the optimum level of Fs was always at a moderate light intensity. By using the modulated fluorescence technique, the system with all closed (Flm) or open reaction center (Flo) were measured in steady state conditions. Each experimentally measured fluorescence yield was separated into a fluorescence emission of open (Fopen = Flo,(1—Vs)) and closed (Fclosed = (Flm . Vs)) reaction center (RC) of photosystem II where Vs=(Fs - Flo)/(Flm - Flo) is the function of fraction of closed reaction centers. With increasing light intensity, the fraction of open RC decreased while the fraction of closed RC increased. Maximum quantum efficiency (ΦPo) and actual quantum efficiency (ΦP) decreased by increasing light intensity. An optimum level of Fs was observed, when the fraction of closed reaction centers Vs of each sample was about 0.2 showing a common quenching mechanism which determines the fluorescence properties under steady state condition. This explains the apparent phenomenological contradiction that the fluorescence yield under steady state conditions can increase or decrease upon an increase of actinic ligh

A graphical simulation software for instruction in cardiovascular mechanics physiology

<p>Abstract</p> <p>Background</p> <p>Computer supported, interactive e-learning systems are widely used in the teaching of physiology. However, the currently available complimentary software tools in the field of the physiology of cardiovascular mechanics have not yet been adapted to the latest systems software. Therefore, a simple-to-use replacement for undergraduate and graduate students' education was needed, including an up-to-date graphical software that is validated and field-tested.</p> <p>Methods</p> <p>Software compatible to Windows, based on modified versions of existing mathematical algorithms, has been newly developed. Testing was performed during a full term of physiological lecturing to medical and biology students.</p> <p>Results</p> <p>The newly developed CLabUZH software models a reduced human cardiovascular loop containing all basic compartments: an isolated heart including an artificial electrical stimulator, main vessels and the peripheral resistive components. Students can alter several physiological parameters interactively. The resulting output variables are printed in x-y diagrams and in addition shown in an animated, graphical model. CLabUZH offers insight into the relations of volume, pressure and time dependency in the circulation and their correlation to the electrocardiogram (ECG). Established mechanisms such as the Frank-Starling Law or the Windkessel Effect are considered in this model. The CLabUZH software is self-contained with no extra installation required and runs on most of today's personal computer systems.</p> <p>Conclusions</p> <p>CLabUZH is a user-friendly interactive computer programme that has proved to be useful in teaching the basic physiological principles of heart mechanics.</p

β-Barrel scaffolds for the grafting of extracellular loops from G-protein-coupled receptors

Owing to the difficulties in production and purification of G-protein-coupled receptors (GPCRs), relatively little structural information is available about this class of receptors. Here we aim at developing small chimeric proteins, displaying the extracellular ligand-binding motifs of a human GPCR, the Y receptor. This allows the study of ligand-receptor interactions in simplified systems. We present comprehensive information on the use of transmembrane (OmpA) and soluble (Blc) β-barrel scaffolds. Whereas Blc appeared to be not fully compatible with our approach, owing to problems with refolding of the hybrid constructs, loop-grafted versions of OmpA delivered encouraging results. Previously, we described a chimeric construct based on OmpA displaying all three extracellular Y1 receptor loops in different topologies and showing moderate affinity to one of the natural ligands. Now, we present detailed data on the interaction of these constructs with several Y receptor ligands along with data on new constructs. Our findings suggest a common binding mode for all ligands, which is mediated through the C-terminal residues of the peptide ligand, supporting the functional validity of these hybrid receptors. The observed binding affinities, however, are well below those observed for the natural receptors, clearly indicating limitations in mimicking the natural system

β-Barrel scaffolds for the grafting of extracellular loops from G-protein-coupled receptors

Owing to the difficulties in production and purification of G-protein-coupled receptors (GPCRs), relatively little structural information is available about this class of receptors. Here we aim at developing small chimeric proteins, displaying the extracellular ligand-binding motifs of a human GPCR, the Y receptor. This allows the study of ligand-receptor interactions in simplified systems. We present comprehensive information on the use of transmembrane (OmpA) and soluble (Blc) β-barrel scaffolds. Whereas Blc appeared to be not fully compatible with our approach, owing to problems with refolding of the hybrid constructs, loop-grafted versions of OmpA delivered encouraging results. Previously, we described a chimeric construct based on OmpA displaying all three extracellular Y1 receptor loops in different topologies and showing moderate affinity to one of the natural ligands. Now, we present detailed data on the interaction of these constructs with several Y receptor ligands along with data on new constructs. Our findings suggest a common binding mode for all ligands, which is mediated through the C-terminal residues of the peptide ligand, supporting the functional validity of these hybrid receptors. The observed binding affinities, however, are well below those observed for the natural receptors, clearly indicating limitations in mimicking the natural system

Antiplasmodial activity of a series of 1,3,5-triazine-substituted polyamines

Polyamine biosynthesis and function has been shown to be a good drug target in some parasitic protozoa and it is proposed that the pathway might also represent a target in the malaria parasite Plasmodium falciparum. A series of 1,3,5-triazine-substituted polyamine analogues were tested for activity against Plasmodium falciparum in vitro. The series showed activity against the parasites and were generally more active against the chloroquine-resistant line K1 than the chloroquine-susceptible line NF54. Simple unbranched analogues had better activity than analogues carrying branched or cyclic central chains. Addition of multiple triazine units in general led to increased activity of the compound

Towards Weyl fermions on the lattice without artefacts

In spite of the breakthrough in non-perturbative chiral gauge theories during the last decade, the present formulation has stubborn artefacts. Independently of the fermion representation one is confronted with unwanted CP violation and infinitely many undetermined weight factors. Renormalization group identifies the culprit. We demonstrate the procedure on Weyl fermions in a real representation

Operationalizing COLREGs in SMART ship navigation

The maritime industry is undergoing a transformation driven by digitalization and connectivity. The technological realization of Maritime Autonomous Surface Ships (MASS) presents significant challenges for the maritime human factors research community. These challenges relate to system design, human-automation interaction, stakeholder training, use and acceptance of new technology systems, and on a larger scale, how the regulatory framework, including the Collision Regulations (COLREGs) will be impacted within a MASS system. Decision support is the next step in the transformation towards more connected ships, however, such systems for navigation are largely unexplored from the users’ perspective.The decision support system studied in this project was developed by W\ue4rtsil\ue4 and is called Advanced Intelligent Manoeuvring (AIM), aligning with “low-level automation” or Level 1 (out of a 4-level progression) of MASS. AIM can generate suggestions for course or speed alterations based on data from surrounding traffic. A full-mission bridge simulator study was conducted at Chalmers University of Technology in Gothenburg, Sweden with nineteen Swedish navigators. Three traffic scenarios each with three ships were completed in both baseline (no AIM) and AIM conditions. A mixed methods data collection and analysis approach was employed using questionnaires, collective interviews, and an evaluation of the ship tracks. The results show that the navigators perceive AIM as an advisory tool, to visualize how traffic situations could unfold, an outcome currently difficult for most navigators to conceive. This report discusses the present and near future of the maritime sociotechnical system, highlighting the benefits of automation, while remaining vigilant about the potential dangers

Electroencephalogram approximate entropy influenced by both age and sleep

The use of information-based measures to assess changes in conscious state is an increasingly popular topic. Though recent results have seemed to justify the merits of such methods, little has been done to investigate the applicability of such measures to children. For our work, we used the approximate entropy (ApEn), a measure previously shown to correlate with changes in conscious state when applied to the electroencephalogram (EEG), and sought to confirm whether previously reported trends in adult ApEn values across wake and sleep were present in children. Besides validating the prior findings that ApEn decreases from wake to sleep (including wake, rapid eye movement (REM) sleep, and non-REM sleep) in adults, we found that previously reported ApEn decreases across vigilance states in adults were also present in children (ApEn trends for both age groups: wake > REM sleep > non-REM sleep). When comparing ApEn values between age groups, adults had significantly larger ApEn values than children during wakefulness. After the application of an 8 Hz high-pass filter to the EEG signal, ApEn values were recalculated. The number of electrodes with significant vigilance state effects dropped from all 109 electrodes with the original 1 Hz filter to 1 electrode with the 8 Hz filter. The number of electrodes with significant age effects dropped from 10 to 4. Our results support the notion that ApEn can reliably distinguish between vigilance states, with low-frequency sleep-related oscillations implicated as the driver of changes between vigilance states. We suggest that the observed differences between adult and child ApEn values during wake may reflect differences in connectivity between age groups, a factor which may be important in the use of EEG to measure consciousness