Merging morphology, molecules and modelling: A unifying approach for understanding the common cat flea (Ctenocephalides felis) and related species worldwide

The genus Ctenocephalides Stiles and Collins, 1930 contains the most ubiquitous and significant flea ectoparasites worldwide. The common cat flea Ctenocephalides felis (Bouché, 1835) is the most cosmopolitan species within the genus and invades human environments by infesting cats and dogs globally. This species causes significant dermatological pathology to pets and is a vector of zoonotic pathogens including Rickettsia felis, Bartonella spp. and the plague (Yersinia pestis) in endemic regions. Additionally, the costs to pet owners for annual flea control amounts to USD$15 billion worldwide. Despite the global medical, veterinary and economic significance of the cat flea, prior to this work little was known about its origins and how it came to be the most pervasive flea species on earth. The primary objective of this thesis was to amass a global collection of Ctenocephalides fleas from cats and dogs to fill the gaps in our knowledge relating to the taxonomy, phylogenetics and vector role of these important parasites. In this body of work, I demonstrate the importance of an integrated morphological and molecular approach for research on parasite and vector species. By marrying morphological taxonomy with molecular systematics and phylogeographic analyses, I resolve the taxonomy of C. felis and demonstrate cryptic diversity within the species that may have implications for zoonotic pathogen transmission. I show that from out-of-Africa origins, human movement and bioclimatic affinities define and conserve globally discrete lineages of C. felis. This work is the most comprehensive survey of global Ctenocephalides fleas thus far and the first to combine morphology with molecules for the analysis of the genus. The research provides a framework for the investigation of any unresolved taxa, particularly for globally distributed groups that impact upon human health, animal health, agriculture and global economics. The outcomes of this research make a significant contribution to the field of medical and veterinary entomology by providing taxonomic resolution of C. felis and by detailing the most effective and exhaustive technique for taxonomic inquiry of other medically or veterinary relevant arthropods. Using C. felis as a model, the work sheds light on the underlying mechanisms of evolutionary dispersal and population establishment of cosmopolitan insect species

On the analysis of tuberculosis studies with intermittent missing sputum data

In randomized studies evaluating treatments for tuberculosis (TB), individuals are scheduled to be routinely evaluated for the presence of TB using sputum cultures. One important endpoint in such studies is the time of culture conversion, the first visit at which a patient’s sputum culture is negative and remains negative. This article addresses how to draw inference about treatment effects when sputum cultures are intermittently missing on some patients. We discuss inference under a novel benchmark assumption and under a class of assumptions indexed by a treatment-specific sensitivity parameter that quantify departures from the benchmark assumption. We motivate and illustrate our approach using data from a randomized trial comparing the effectiveness of two treatments for adult TB patients in Brazil.Fil: Scharfstein, Daniel. University Johns Hopkins; Estados UnidosFil: Rotnitzky, Andrea Gloria. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Torcuato Di Tella. Departamento de Economía; ArgentinaFil: Abraham, Maria. Statistics Collaborative; Estados UnidosFil: McDermott, Aidan. University Johns Hopkins; Estados UnidosFil: Chaisson, Richard. University Johns Hopkins; Estados UnidosFil: Geiter, Lawrence. Otsuka Novel Products; Estados Unido

FORMER FOSTER YOUTH PERSPECTIVES ON STRENGTHS AND NEEDED SERVICES OF THE FOSTER CARE SYSTEM

This study examined former foster youth’s perceptions of the skills and services they received while they were in the foster care system. More specifically the efficacy of these services, and what services and skills they believed would have been helpful to assist them in their transition into independent living. A qualitative design was used, and semi-structured face-to-face and telephone interviews were conducted with ten former foster youth who aged out of foster care at age eighteen through twenty-one. Two males and eight females from diverse backgrounds participated in this study. Participants were recruited through availability and snowball sampling at community agencies, college campuses, and the community. This study found that participants experienced a difficult time transitioning from foster care to independent living, felt unprepared after leaving foster care, needing additional services, and expressed wanting to have received more in depth financial management skills. This study recommends providing additional independent living skills, social support, and participation in the Independent Living Program as part of foster youth’s case plan when preparing to transition out of foster care into independent living

Mild Cognitive Impairment: Implications of Diagnosis

Mild cognitive impairment (MCI) reflects the interim stage between normal cognitive functioning and more severe and irreversible cognitive decline that can be associated with dementia. Prevalence estimates suggest 12% to 18% of older adults (>60 years) develop MCI [1]. Risk factors for MCI include being male, older age, lower education level (i.e., lower cognitive reserve), diabetes and hypertension, apolipoprotein E (APOE) e4 genotype, and sleep disorders [2]. MCI presents as four phenotypes: amnestic single, amnestic multiple, non-amnestic single and non-amnestic multiple, and classification depends upon the affected cognitive domain. MCI is a common precursor to Alzheimer’s disease and other neurodegenerative disorders including dementia with Lewy bodies, frontotemporal dementia, and vascular cognitive impairment [1]

Fermion masses and symmetry breaking of a U(2) flavour symmetry

We show how a specific sequential breaking pattern of a U(2) flavour symmetry occurs automatically in a broad framework. The relative orientation in U(2) space of the spurion fields that breaks the U(2) symmetry is uniquely fixed, thus determining the form of the fermion mass matrices in a predictive way.Comment: 9 pages, uses amsmath.st

Spillover effects of innovation and entrepreneurial activity on income inequality in developing countries: A spatial panel approach

This paper investigated the spatial effects of innovation and entrepreneurial activity on income inequality of 64 middle-and-low-income countries and 25 high-income countries from 2000 to 2016. Spatial panel methods are used to address the issues of spatial dependency and spillover effects among neighboring countries. We find the following: (1) Evidence of spatial correlations in income inequality across countries. (2) A positive direct effect between innovation and inequality but a positive feedback from innovation. (3) The relationship between entrepreneurial activity and inequality is mixed. The relationship is positive if entrepreneurial activity is proxied by self-employment but negative if measured by entry rate. Both produced a negative feedback effect, which suggests that entrepreneurial activity is linked to rising inequality in developing countries. (4) A positive spillover effect from innovation and negative spillover effect from self-employment. We also investigated whether the linkages between innovation\u2013inequality and entrepreneurial activity\u2013inequality are subject to a country-level institutional quality. The findings suggest that the interaction terms have negative effects on income inequality. For policy implications, innovation sharing should be encouraged to reduce monopoly power that increases the tendency for wealth accumulation. Another possible solution to increase entrepreneurial activities while reducing inequality is for governments in developing countries to offer various schemes targeted at the poor, especially finance

Reducing orbital eccentricity of precessing black-hole binaries

Building initial conditions for generic binary black-hole evolutions without initial spurious eccentricity remains a challenge for numerical-relativity simulations. This problem can be overcome by applying an eccentricity-removal procedure which consists in evolving the binary for a couple of orbits, estimating the eccentricity, and then correcting the initial conditions. The presence of spins can complicate this procedure. As predicted by post-Newtonian theory, spin-spin interactions and precession prevent the binary from moving along an adiabatic sequence of spherical orbits, inducing oscillations in the radial separation and in the orbital frequency. However, spin-induced oscillations occur at approximately twice the orbital frequency, therefore they can be distinguished from the initial spurious eccentricity, which occurs at approximately the orbital frequency. We develop a new removal procedure based on the derivative of the orbital frequency and find that it is successful in reducing the eccentricity measured in the orbital frequency to less than 0.0001 when moderate spins are present. We test this new procedure using numerical-relativity simulations of binary black holes with mass ratios 1.5 and 3, spin magnitude 0.5 and various spin orientations. The numerical simulations exhibit spin-induced oscillations in the dynamics at approximately twice the orbital frequency. Oscillations of similar frequency are also visible in the gravitational-wave phase and frequency of the dominant mode.Comment: 17 pages, 11 figures, fixed typo

Inspiral-merger-ringdown waveforms of spinning, precessing black-hole binaries in the effective-one-body formalism

We describe a general procedure to generate spinning, precessing waveforms that include inspiral, merger and ringdown stages in the effective-one-body (EOB) approach. The procedure uses a precessing frame in which precession-induced amplitude and phase modulations are minimized, and an inertial frame, aligned with the spin of the final black hole, in which we carry out the matching of the inspiral-plunge to merger-ringdown waveforms. As a first application, we build spinning, precessing EOB waveforms for the gravitational modes l=2 such that in the nonprecessing limit those waveforms agree with the EOB waveforms recently calibrated to numerical-relativity waveforms. Without recalibrating the EOB model, we then compare EOB and post-Newtonian precessing waveforms to two numerical-relativity waveforms produced by the Caltech-Cornell-CITA collaboration. The numerical waveforms are strongly precessing and have 35 and 65 gravitational-wave cycles. We find a remarkable agreement between EOB and numerical-relativity precessing waveforms and spins' evolutions. The phase difference is ~ 0.2 rad at merger, while the mismatches, computed using the advanced-LIGO noise spectral density, are below 2% when maximizing only on the time and phase at coalescence and on the polarization angle.Comment: 17 pages, 10 figure

Nonlinear bubble dynamics

The standard approach to the analysis of the pulsations of a driven gas bubble is to assume that the pressure within the bubble follows a polytropic relation of the form p=p0(R0/R)3?, where p is the pressure within the bubble, R is the radius, ? is the polytropic exponent, and the subscript zero indicates equilibrium values. For nonlinear oscillations of the gas bubble, however, this approximation has several limitations and needs to be reconsidered. A new formulation of the dynamics of bubble oscillations is presented in which the internal pressure is obtained numerically and the polytropic approximation is no longer required. Several comparisons are given of the two formulations, which describe in some detail the limitations of the polytropic approximation

Victoria\u27s Little Secret: Addressing Child Labor

This mini-case outlines a series of articles that ran in Bloomberg outlining the use of child slave labor in the fair trade cotton fields of Burkina Faso that had been used exclusively in Victoria’s Secret products. Giving students and opportunity to develop strategies and tactics that respond to a real-world public relations issue, this case also lets students explore the CSR issues inherent in a firm’s supply chain. Although trying to do the “right thing” Victoria’s Secret got caught up in the certification dilemma that many firms face. Part II of vide