Programming Language Feature Agglomeration

Feature-creep is a well-known phenomenon in software systems. In this paper, we argue that feature-creep also occurs in the domain of programming languages. Recent languages are more expressive than earlier languages. However recent languages generally extend rather than replace the syntax (sometimes) and semantics (almost always) of earlier languages. We demonstrate this trend of agglomeration in a sequence of languages comprising Pascal, C, Java, and Scala. These are all block-structured Algol-derived languages, with earlier languages providing explicit inspiration for later ones. We present empirical evidence from several language-specific sources, including grammar definitions and canonical manuals. The evidence suggests that there is a trend of increasing complexity in modern languages that have evolved from earlier languages

Outlook for detection of GW inspirals by GRB-triggered searches in the Advanced detector era

Short, hard gamma-ray bursts (GRBs) are believed to originate from the coalescence of two neutron stars (NSs) or a NS and a black hole (BH). If this scenario is correct, then short GRBs will be accompanied by the emission of strong gravitational waves (GWs), detectable by GW observatories such as LIGO, Virgo, KAGRA, and LIGO-India. As compared with blind, all-sky, all-time GW searches, externally triggered searches for GW counterparts to short GRBs have the advantages of both significantly reduced detection threshold due to known time and sky location and enhanced GW amplitude because of face-on orientation. Based on the distribution of signal-to-noise ratios in candidate compact binary coalescence events in the most recent joint LIGO-Virgo data, our analytic estimates, and our Monte Carlo simulations, we find an effective sensitive volume for GRB-triggered searches that is about 2 times greater than for an all-sky, all-time search. For NS-NS systems, a jet angle of 20 degrees, a gamma-ray satellite field of view of 10% of the sky, and priors with generally precessing spin, this doubles the number of NS-NS short-GRB and NS-BH short-GRB associations, to ~3-4% of all detections of NS-NSs and NS-BHs. We also investigate the power of tests for statistical excesses in lists of subthreshold events, and show that these are unlikely to reveal a subthreshold population until finding GW associations to short GRBs is already routine. Finally, we provide useful formulas for calculating the prior distribution of GW amplitudes from a compact binary coalescence, for a given GW detector network and given sky location.Comment: 14 pages, 4 figures, published in PRD; this version includes changes in final copyedited articl

Emergence of market structures in financial markets and their impact on trade, welfare, and financial stability

Die Dissertation ist kumulativ und besteht aus vier eigenständigen Aufsätzen. Der erste Aufsatz beschreibt den Handel auf außerbörslichen Märkten mit Suchbeschränkungen. Händler, die Transaktionen für Investoren vermitteln, bilden endogen heterogene Suchcharakteristika aus, die zu einer Kern-Peripherie Marktstruktur führen. Kernhändler handeln deutlich häufiger und erzielen deutlich höhere Handelsmargen sowie Gewinne als Peripheriehändler. Zudem handeln Händler unterschiedlicher Suchcharakteristika mit Investoren zu unterschiedlichen Preisen. Der zweite Aufsatz beschreibt den Preiswettbewerb unter Händlern auf außerbörslichen Märkten. Händler, die Transaktionen für Investoren vermitteln, bilden endogen heterogene Charakteristika aus, die unter gewissen Umständen zu einer Kern-Peripherie Marktstruktur führen. Kernhändler handeln deutlich häufiger als Peripheriehändler. Außerdem erzielen Kernhändler höhere Handelsmargen als Peripheriehändler, obwohl sie engere Geld-Briefkursspannen anbieten. Der dritte Aufsatz beschreibt den Handel auf Börsenmärkten. Händler mit weitem Zeithorizont handeln zu geringeren effektiven Handelskosten als Händler mit kurzem Zeithorizont, was Anreize für den außerbörslichen Handel schafft und zu heterogenen Zeithorizonten im Gleichgewicht führt. Eine Kern-Peripherie-Händlerstruktur bildet sich endogen. Der vierte Aufsatz untersucht Interbanken-Ansteckungseffekte, die aufgrund von panikgetriebenen Geldabflüssen entstehen und stellt diese in Bezug auf das zugrundeliegende Interbanknetzwerk. Drei Schlussfolgerungen für die Bankenregulierung und Krisenmanagement werden abgeleitet

Analysing effects of spatiotemporally distributed species interactions in Maculinea systems

We analyse effects of species-interaction and spatiotemporal host distribution on persistence of Maculinea populations at isolated habitat sites. Maculinea butterflies are parasites of Myrmica ants. The butterfly caterpillars infest host ant nest in the vicinity of their initial oviposition plant. Thus, spatial distribution of initial host plants (oviposition plants), implies a spatial distribution of parasitism. We develop a generic spatially-explicit rule-based simulation model for a Maculinea systems, to analyse the influence of different spatially relevant parameters on the performance of a Maculinea population. Parameter variation considers spatial host plant distribution, initial spatial host ant distribution and budding-range, which defines the probability distribution of colonising distances of ants. In simulation runs, it can be seen that the spatial distribution of host ants adapts to the spatially distributed parasitism from Maculinea caterpillars. Areas without host plants (unexploited areas) are completely inhabited by host ants. In areas with host plants (exploited areas) mean density of host ants is lower. Ant nests show dynamics. They are abandoned or nest sites are recolonised. Because of spatial segregation of exploitable and non-exploitable areas and by small scale dispersal of host ants (budding), areas of different effectiveness for Maculinea population performance can be distinguished on a Maculinea habitat site: These are reproductive area, buffer, sink and non-contributing area. Consequently, number of host plants is not the only decisive factor for performance of a Maculinea population. As well it is important how well empty nest sites in the vicinity of host plants can be colonised by host ants. We find two different mechanisms, which limit re-growth of the Maculinea butterfly population and lead to different types of dynamics. Population viability analysis (PVA) is a standard method for single species systems. However, the Maculinea system consists of interacting species with more complex dynamics. There is still no standardised methodology for PVA of multi-species systems. We derive a phenomenological description of distributions of extinction times for populations in a large class of systems of interacting species. We find in analytical calculations that the long term behaviour of distributions of times to extinction in multi-species systems can be analysed with the ln(1-P_{0})-method suggested for single species systems. Thus, this method can be transferred. Comparing distributions of times to extinction of single and interacting species, we find that long term extinction of established populations follows a similar process. However, on short time-scales, population cycles modulate extinction risk. In systems of interacting species, an initial transient phase can have strong influence on persistence of the population. In simulations of the Macu model, we observe that it takes up to 50 generations until the system reaches its established state. This can lead to a bottleneck of the population. We develop a landscape analysis method for multi-species systems. For that purpose, suitability of different landscapes is assessed for their ability to sustain particular populations. Suitability is measured by population persistence. Therefore, dynamics of the system and requirements of the populations are taken into account when assessing suitability. This method is applied to assess effects of the influence of different spatially relevant parameters. No major effects of initial host ant distribution on persistence of Maculinea populations can be found. In contrast, spatial distribution of host plants has a main effect. Thus, the host plant distribution can be considered as landscape structure of the Maculinea system on the site. Rules of thumb for suitable structures of host plant distributions and a spatial index are given. In general heterogeneous host plant distributions of intermediate density are a good option

Analytic approximations to the phase diagram of the Jaynes-Cummings-Hubbard model with application to ion chains

We discuss analytic approximations to the ground state phase diagram of the homogeneous Jaynes-Cummings-Hubbard (JCH) Hamiltonian with general short-range hopping. The JCH model describes e.g. radial phonon excitations of a linear chain of ions coupled to an external laser field tuned to the red motional sideband with Coulomb mediated hopping or an array of high-$Q$ coupled cavities containing a two-level atom and photons. Specifically we consider the cases of a linear array of coupled cavities and a linear ion chain. We derive approximate analytic expressions for the boundaries between Mott-insulating and superfluid phases and give explicit expressions for the critical value of the hopping amplitude within the different approximation schemes. In the case of an array of cavities, which is represented by the standard JCH model we compare both approximations to numerical data from density-matrix renormalization group (DMRG) calculations.Comment: 9 pages, 5 figures, extended and corrected second versio

Introduction d’un programme de formation en gestion du changement pour les résidents en médecine familiale–un projet de démonstration

Implication Statement The project presents an innovative mixed learning approach program to provide basic change management training for family medicine residents.  Developed by a team of faculty experts in the Department of Family Medicine at the University of Manitoba, this three-to-four-hour training program provided residents an understanding of an approach to change management that systematically plans, implements, and evaluates new initiatives in healthcare settings. Students reported that change management is important for their success as healthcare professionals. This program could easily be replicated.Énoncé des implications de la recherche Ce projet présente un programme novateur fondé sur une approche d’apprentissage mixte visant à offrir une formation de base en gestion du changement aux résidents en médecine familiale. Élaborée par une équipe de professeurs experts du département de médecine familiale de l’Université du Manitoba, cette formation d’une durée de trois à quatre heures a permis aux résidents de se familiariser avec une approche de la gestion du changement qui consiste à planifier, à mettre en œuvre et à évaluer systématiquement de nouvelles initiatives en milieu clinique. Les étudiants estiment que la gestion du changement est un facteur important pour leur réussite en tant que professionnels de la santé. Ce programme peut aisément être transposé

Managing uncertainty in complex stochastic models: design and emulation of a Rabies model

In this paper we present a novel method for emulating a stochastic, or random output, computer model and show its application to a complex rabies model. The method is evaluated both in terms of accuracy and computational efficiency on synthetic data and the rabies model. We address the issue of experimental design and provide empirical evidence on the effectiveness of utilizing replicate model evaluations compared to a space-filling design. We employ the Mahalanobis error measure to validate the heteroscedastic Gaussian process based emulator predictions for both the mean and (co)variance. The emulator allows efficient screening to identify important model inputs and better understanding of the complex behaviour of the rabies model

Sept conseils pour la supervision clinique à l’ère de la COVID

Virtual care (VC) rapidly has become the preferred care model in family medicine settings during the COVID-19 pandemic.  Both residents and preceptors must rapidly adapt and develop new skills to provide and supervise virtual care. The College of Family Physicians of Canada (CFPC) created a VC supervision guide for family medicine residents and preceptors by quickly mobilizing a consensus driven approach leveraging existing CFPC educational committees, representing a broad range of teachers and residents in the country. The guide can be adapted to other settings and is provided in the hopes of being helpful to all preceptors providing VC and (virtual) supervision during the pandemic. Pendant la pandémie de la COVID-19, les soins virtuels (SV) sont rapidement devenus le modèle de soins préféré en médecine familiale. Tant les résidents que les précepteurs doivent promptement s'adapter et développer de nouvelles habiletés pour fournir et superviser les soins virtuels. Sans tarder, le Collège des médecins de famille du Canada (CMFC) a mobilisé les comités éducatifs existants du CMFC, représentant un large éventail d'enseignants et de résidents du pays, pour créer, par le biais d’une approche consensuelle, un guide de la supervision des soins virtuels à l’intention des résidents et des superviseurs en médecine familiale. Le guide peut être adapté à d'autres contextes et il est offert dans l'espoir qu’il sera utile à tous les superviseurs qui prodiguent et supervisent des soins virtuels pendant la pandémie

Covariance Matrix Estimation for the Cryo-EM Heterogeneity Problem

In cryo-electron microscopy (cryo-EM), a microscope generates a top view of a sample of randomly oriented copies of a molecule. The problem of single particle reconstruction (SPR) from cryo-EM is to use the resulting set of noisy two-dimensional projection images taken at unknown directions to reconstruct the three-dimensional (3D) structure of the molecule. In some situations, the molecule under examination exhibits structural variability, which poses a fundamental challenge in SPR. The heterogeneity problem is the task of mapping the space of conformational states of a molecule. It has been previously suggested that the leading eigenvectors of the covariance matrix of the 3D molecules can be used to solve the heterogeneity problem. Estimating the covariance matrix is challenging, since only projections of the molecules are observed, but not the molecules themselves. In this paper, we formulate a general problem of covariance estimation from noisy projections of samples. This problem has intimate connections with matrix completion problems and high-dimensional principal component analysis. We propose an estimator and prove its consistency. When there are finitely many heterogeneity classes, the spectrum of the estimated covariance matrix reveals the number of classes. The estimator can be found as the solution to a certain linear system. In the cryo-EM case, the linear operator to be inverted, which we term the projection covariance transform, is an important object in covariance estimation for tomographic problems involving structural variation. Inverting it involves applying a filter akin to the ramp filter in tomography. We design a basis in which this linear operator is sparse and thus can be tractably inverted despite its large size. We demonstrate via numerical experiments on synthetic datasets the robustness of our algorithm to high levels of noise