Uniqueness, intractability and exact algorithms: reflections on level-k phylogenetic networks

Phylogenetic networks provide a way to describe and visualize evolutionary histories that have undergone so-called reticulate evolutionary events such as recombination, hybridization or horizontal gene transfer. The level k of a network determines how non-treelike the evolution can be, with level-0 networks being trees. We study the problem of constructing level-k phylogenetic networks from triplets, i.e. phylogenetic trees for three leaves (taxa). We give, for each k, a level-k network that is uniquely defined by its triplets. We demonstrate the applicability of this result by using it to prove that (1) for all k of at least one it is NP-hard to construct a level-k network consistent with all input triplets, and (2) for all k it is NP-hard to construct a level-k network consistent with a maximum number of input triplets, even when the input is dense. As a response to this intractability we give an exact algorithm for constructing level-1 networks consistent with a maximum number of input triplets

A Sagittarius-Induced Origin for the Monoceros Ring

The Monoceros ring is a collection of stars in nearly-circular orbits at roughly 18 kpc from the Galactic center. It may have originated (i) as the response of the disc to perturbations excited by satellite companions or (ii) from the tidal debris of a disrupted dwarf galaxy. The metallicity of Monoceros stars differs from that of disc stars at comparable Galactocentric distances, an observation that disfavours the first scenario. On the other hand, circular orbits are difficult to accommodate in the tidal-disruption scenario, since it requires a satellite which at the time of disruption was itself in a nearly circular orbit. Such satellite could not have formed at the location of the ring and, given its low mass, dynamical friction is unlikely to have played a major role in its orbital evolution. We search cosmological simulations for low-mass satellites in nearly-circular orbits and find that they result, almost invariably, from orbital changes induced by collisions with more massive satellites: the radius of the circular orbit thus traces the galactocentric distance of the collision. Interestingly, the Sagittarius dwarf, one of the most luminous satellites of the Milky Way, is in a polar orbit that crosses the Galactic plane at roughly the same Galactocentric distance as Monoceros. We use idealized simulations to demonstrate that an encounter with Sagittarius might well have led to the circularization and subsequent tidal demise of the progenitor of the Monoceros ring.Comment: 6 pages, 4 figures, to match version published in MNRAS Letters (http://onlinelibrary.wiley.com/doi/10.1111/j.1745-3933.2011.01035.x/abstract

CO2 Emissions Trading in Buildings and the Landlord-Tenant Dilemma: How to solve it

CO2 EMISSIONS TRADING IN BUILDINGS AND THE LANDLORD-TENANT DILEMMA: HOW TO SOLVE IT CO2 Emissions Trading in Buildings and the Landlord-Tenant Dilemma: How to solve it / Thomaßen, Georg (Rights reserved) ( -

The bedrock topography of Gries- and Findelengletscher

Knowledge of the ice thickness distribution of glaciers is important for glaciological and hydrological applications. In this contribution, we present two updated bedrock topographies and ice thickness distributions for Gries- and Findelengletscher, Switzerland. The results are based on ground-penetrating radar (GPR) measurements collected in spring 2015 and already-existing data. The GPR data are analysed using ReflexW software and interpolated by using the ice thickness estimation method (ITEM). ITEM calculates the thickness distribution by using principles of ice flow dynamics and characteristics of the glacier surface. We show that using such a technique has a significance advantage compared to a direct interpolation of the measurements, especially for glacier areas that are sparsely covered by GPR data. The uncertainties deriving from both the interpretation of the GPR signal and the spatial interpolation through ITEM are quantified separately, showing that, in our case, GPR signal interpretation is a major source of uncertainty. The results show a total glacier volume of 0.28±0.06 and 1.00±0.34 km3 for Gries- and Findelengletscher, respectively, with corresponding average ice thicknesses of 56.8±12.7 and 56.3±19.6 m

Krankenfürsorge im Spannungsfeld von Medizin, Glauben und Gesundheitspolitik : Die Gemeinschaft der Missionshelferinnen, 1952–1994

Die vorliegende Studie nimmt für den Zeitraum von den Vorbereitungsmaßnahmen zur Gründung der Gemeinschaft der Missionshelferinnen im Jahr 1952 bis zu deren Ausscheiden aus dem Missionsärztlichen Institut Würzburg im Jahr 1994 die von ihr betreuten Gesundheitseinrichtungen und Missionshospitäler in Afrika und Asien in den Blick. Der Gemeinschaft der Missionshelferinnen gehörten Frauen aus den Gesundheitsberufen an und sie war Teil des Missionsärztlichen Instituts Würzburg. Die Korrespondenz zwischen den Gesundheitsfachkräften vor Ort und der koordinierenden Stelle in Würzburg stellt das zentrale Archivmaterial dieser Studie dar. Über einen Zeitraum von vier Jahrzehnten zeigen sich darin dynamische Transformations- und Adaptationsprozesse von Begriffen, Verhaltensmustern, Konzepten und Strategien der handelnden Akteure und Institutionen sowie eine Neuausrichtung kirchlicher Gesundheitsarbeit. In dieser postkolonialen Studie aus dem Querschnittsbereich der Geschichte zur Entwicklungszusammenarbeit, der Missionsmedizingeschichte und der außereuropäischen Krankenhausgeschichte werden folgende Themenfelder untersucht: Missionshospitäler während und nach der Dekolonialisierung, katholische Missionsmedizin, Frauen als Trägerinnen des missionsärztlichen Gedankens, religiös motivierte Gesundheitsfachkräfte in der Entwicklungszusammenarbeit und die Krankenpflege als Teil der Missionsmedizin. Das Verhältnis der kirchlichen Gesundheitseinrichtungen zu staatlichen Institutionen war bestimmt von dem Wunsch nach Kooperation unter Wahrung der Eigenständigkeit der Gesundheitseinrichtungen. Im Zuge des Wandels des Missionsmedizinbegriffes gewann der medizinisch-krankenpflegerische Aspekt an Bedeutung. Missionskrankenhäuser etablierten sich und beförderten sowohl eine Bürokratisierung als auch einen Aufschwung der Krankenversorgung in den Gesundheitseinrichtungen der postkolonialen Mission. Kirchliche Gesundheitseinrichtungen waren Vertreter der Modernisierungstheorie und wurden zu einem integralen Bestandteil der Entwicklungszusammenarbeit. Im Zuge des Wandels des Entwicklungsbegriffes wurde die kurative Medizin in den Missionskrankenhäusern um das Gesundheitskonzept der Primary health care ergänzt. Dabei konkurrierten beide Konzepte. Der Wandel des Entwicklungsbegriffes beförderte darüber hinaus die Übergabe von Aufgaben- und Verantwortungsbereichen an einheimisches Personal innerhalb der Missionshospitäler und Gesundheitsprojekte. Die Missionshospitäler waren Orte des Wissensaustausches und der Ausbildung. So wurden Ausbildungsstätten geschaffen, in denen das Wissen westlicher Medizin und Krankenpflege vermittelt wurde. Die Preispolitik der kirchlichen Gesundheitseinrichtungen war aus karitativen Gründen nicht wirtschaftlich und führte sowohl zu einer Abhängigkeit von ausländischen Geldgebern als auch zu Konflikten mit anderen Gesundheitsanbietern. Typisch für die kirchlichen Gesundheitseinrichtungen war der hybride Charakter aus Medizin und christlichem Glauben. Unabhängig von der Religionszugehörigkeit wurden alle Personen in den kirchlichen Gesundheitseinrichtungen behandelt. Missionsstrategische Überlegungen der Missionsdiözesen nahmen Einfluss auf die Planung der Krankenhäuser. Bei der Auswahl des Personals war die medizinische Qualifikation entscheidend. Gleichzeitig wurde eine Achtung der Ausrichtung als katholisches Missionskrankenhaus vom Personal eingefordert. Eine Affinität kirchlicher Gesundheitseinrichtungen für die Lepraarbeit, die Gynäkologie und die Geburtshilfe ist zu konstatieren. Unterschiede bei Gesundheits- und Krankheitsvorstellungen zwischen den Anhängern traditioneller Heilkunde und denen westlicher Medizin erschwerten den Aufbau krankenhauszentrierter Gesundheitsversorgung und die Umsetzung medizinischer Programme im Bereich der Primary health care. Karitative und entwicklungspolitische Denkmuster lagen dem medizinischen Handeln zugrunde, wobei im untersuchten Zeitraum stärker entwicklungspolitisch orientierte Ansätze zu beobachten sind. Missionshospitäler und kirchliche Gesundheitseinrichtungen waren in jedem Falle ein wichtiger Bestandteil der Gesundheitssysteme vor Ort.Health care in the area of conflict between medicine, faith and health policy: The Medical Missionary Society (Gemeinschaft der Missionshelferinnen), 1952-1994 This study deals with the health centres and mission hospitals in Africa and Asia run by the Medical Missionary Society (Gemeinschaft der Missionshelferinnen) in the period 1952-1994. In 1952 the first steps to found the Society were taken and in 1994 the Society left the Würzburg Medical Missionary Institute (Missionsärztliches Institut Würzburg) having been part of it for four decades. The Medical Missionary Society consisted of female health workers. The correspondence of the health workers in the developing countries with the coordinator in Würzburg provides the main basis of this study. Over four decades a process of transformation and adaptation of the ideas, activities, policies and strategies of the participating individuals and institutions as well as a change of health care provided by the Church can be observed. This study of the postcolonial era, which is part of the history of missionary medical work, the history of overseas aid policy and the history of non-European hospitals, analyses the following: Mission hospitals during and after decolonisation, Catholic missionary medical work, the role of women in missionary medical work, religiously motivated health workers in aid to developing countries and nursing care as a part of missionary medical work. The health centres provided by the Church wanted to develop closer institutional links and cooperation with the governments without losing their independence. Traditional notions of medical missionary work had to adapt to new perceptions of health care. Medical and nursing activity in the mission hospitals and health centres became more important. Mission hospitals were established. This resulted in an expansion of bureaucracy and health care in the health centres of postcolonial mission. Health centres provided by the Church were representatives of the theory of modernisation and were part of the international aid to developing countries. Experiences in the developing countries created a new awareness of how development should be understood. This transformation impacted on the health care done in the health centres and mission hospitals. In addition to the policy of practising western curative medicine, new strategies of development policy were born and curative health care was supplemented with elements of preventative medicine. Both concepts competed for the limited financial resources. Gradually, all departments in the health centres and mission hospitals were handed over to indigenous personnel. The mission hospitals were places of training and education. One of the objectives of the mission hospital was to teach knowledge of western medicine and nursing. The pricing policy of the mission hospitals was adjusted according to social factors and based on a charitable point of view. This resulted in a dependence on foreign funding organisations and conflict with local health care providers. The ethos of the mission hospital combined medical practice with Christian faith. The access to the health care offered in the mission hospitals was open to everybody. Missionary strategies of dioceses impacted on the planning of the mission hospitals. The policy of choosing personnel for the hospitals was based on medical qualifications. At the same time the staff was expected to respect the ethical rules of a Catholic mission hospital. The mission hospitals often focused on leprosy work, obstetrics and gynaecology. Different beliefs concerning health and disease among followers of traditional medicine and those of western medicine led to difficulties in running hospitals and in carrying out medically necessary measures with regard to preventative medicine. The motives behind development policies and charitable ones influenced medical work. In the four decades examined in this study it can be stated that health care in the mission hospitals was more and more influenced by conceptions of international aid to developing countries. Mission hospitals and health centres provided by the Church were an important part of local health care systems

Utility of synovial biopsy

Synovial biopsies, gained either by blind needle biopsy or minimally invasive arthroscopy, offer additional information in certain clinical situations where routine assessment has not permitted a certain diagnosis. In research settings, synovial histology and modern applications of molecular biology increase our insight into pathogenesis and enable responses to treatment with new therapeutic agents to be assessed directly at the pathophysiological level. This review focuses on the diagnostic usefulness of synovial biopsies in the light of actual developments

Detailed Kinetic Model for the Reaction of Ethene to Propene on Ni/AlMCM-41

The Ni/AlMCM-41 was prepared and applied as the catalyst for the direct conversion of ethene to propene. Based on the results of the broad experimental study, two reaction networks were compared, one consisting of dimerization, isomerization and metathesis and a modified network suggesting the cracking of long-chain olefins. To correlate the experimentally obtained data, the classical Langmuir-Hinshelwood-Hougen-Watson model was applied for both reaction networks. The second network involving catalytic cracking offers a satisfying prediction of the observed product distributions

Orbital-free Bond Breaking via Machine Learning

Machine learning is used to approximate the kinetic energy of one dimensional diatomics as a functional of the electron density. The functional can accurately dissociate a diatomic, and can be systematically improved with training. Highly accurate self-consistent densities and molecular forces are found, indicating the possibility for ab-initio molecular dynamics simulations

Mitochondrial acclimation potential to ocean acidification and warming of Polar cod (Boreogadus saida) and Atlantic cod (Gadus morhua)

Background: Ocean acidification and warming are happening fast in the Arctic but little is known about the effects of ocean acidification and warming on the physiological performance and survival of Arctic fish. Results: In this study we investigated the metabolic background of performance through analyses of cardiac mitochondrial function in response to control and elevated water temperatures and PCO2 of two gadoid fish species, Polar cod (Boreogadus saida), an endemic Arctic species, and Atlantic cod (Gadus morhua), which is a temperate to cold eurytherm and currently expanding into Arctic waters in the wake of ocean warming. We studied their responses to the above-mentioned drivers and their acclimation potential through analysing the cardiac mitochondrial function in permeabilised cardiac muscle fibres after 4 months of incubation at different temperatures (Polar cod: 0, 3, 6, 8 °C and Atlantic cod: 3, 8, 12, 16 °C), combined with exposure to present (400μatm) and year 2100 (1170μatm) levels of CO2. OXPHOS, proton leak and ATP production efficiency in Polar cod were similar in the groups acclimated at 400μatm and 1170μatm of CO2, while incubation at 8 °C evoked increased proton leak resulting in decreased ATP production efficiency and decreased Complex IV capacity. In contrast, OXPHOS of Atlantic cod increased with temperature without compromising the ATP production efficiency, whereas the combination of high temperature and high PCO2 depressed OXPHOS and ATP production efficiency. Conclusions: Polar cod mitochondrial efficiency decreased at 8 °C while Atlantic cod mitochondria were more resilient to elevated temperature; however, this resilience was constrained by high PCO2. In line with its lower habitat temperature and higher degree of stenothermy, Polar cod has a lower acclimation potential to warming than Atlantic cod