The influence of biological rhythms on host–parasite interactions

Biological rhythms, from circadian control of cellular processes to annual cycles in life history, are a main structural element of biology. Biological rhythms are considered adaptive because they enable organisms to partition activities to cope with, and take advantage of, predictable fluctuations in environmental conditions. A flourishing area of immunology is uncovering rhythms in the immune system of animals, including humans. Given the temporal structure of immunity, and rhythms in parasite activity and disease incidence, we propose that the intersection of chronobiology, disease ecology, and evolutionary biology holds the key to understanding host–parasite interactions. Here, we review host–parasite interactions while explicitly considering biological rhythms, and propose that rhythms: influence within-host infection dynamics and transmission between hosts, might account for diel and annual periodicity in host–parasite systems, and can lead to a host–parasite arms race in the temporal domain

Digital Epidemiology Reveals Global Childhood Disease Seasonality and the Effects of Immunization

ACKNOWLEDGMENTS. We would like to thank Fernando Gonzalez-Dominguez and Gilberto Vaughan for providing the chicken pox case reports from Mexico, and the Estonia Health Board, Department of Communicable Disease Surveillance and Control, for Estonian chicken pox case reports. KB would like to thank Mercedes Pascual, her lab, and Marisa Eisenberg for helpful comments. Jesus Cantu (research assistant, Princeton University) translated and categorized chicken pox searches from Mexico, Thailand, Australia, and the US.Peer reviewedPostprintPostprin

The Drivers of Acute Seasonal Infectious Diseases.

Seasonality is a feature of all ecological systems. Earth's terrestrial and pelagic life has evolved in a highly seasonal abiotic environment with intra-annual variation in photoperiod, temperature, and precipitation, among many other abiotic and biotic factors. Seasonal aspects of mammals and birds include seasonally varying birth rates, seasonal changes in endocrine hormones, and seasonal variation in immunity. One area where seasonal biology is particularly salient is disease ecology. The mechanisms underlying the seasonality of communicable diseases are poorly understood. I propose that much of the unexplained seasonality observed in infectious disease dynamics could be attributed to seasonal biology, including (1) birth seasonality, (2) seasonal variation in immunity, and (3) seasonal cycles in parasite traits and parasite population parameters. In my dissertation, I present work on various aspects of seasonality. In Chapter II, I explored the seasonality of births in human populations and quantified the effects of birth seasonality on measles epidemics. In Chapter III, I reviewed circadian and circannual rhythms in host and parasite populations, and proposed both ecological and evolutionary models for integrating biological rhythms into the study of infectious diseases. In Chapters IV--V, I presented my in-depth ecological studies of poliovirus, a notoriously seasonal summertime infection. I explored geographical variation in polio's seasonality and tested whether human birth seasonality or transmission seasonality drove epidemics of this disease. In addition to studying polio seasonality, I revealed the connection between (i) polio's emergence and human demography, (ii) the geographical distribution of poliovirus and its persistence, and (iii) polio symptomatology and silent chains of transmission. Lastly, I highlighted the public health implications of seasonal transmission by measuring the efficacy of the two polio vaccines and discussing how seasonality can be utilized for vaccine interventions.PhDEcology and Evolutionary BiologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/113643/1/bakkerma_1.pd

Existence and Stability of Symmetric Periodic Simultaneous Binary Collision Orbits in the Planar Pairwise Symmetric Four-Body Problem

We extend our previous analytic existence of a symmetric periodic simultaneous binary collision orbit in a regularized fully symmetric equal mass four-body problem to the analytic existence of a symmetric periodic simultaneous binary collision orbit in a regularized planar pairwise symmetric equal mass four-body problem. We then use a continuation method to numerically find symmetric periodic simultaneous binary collision orbits in a regularized planar pairwise symmetric 1, m, 1, m four-body problem for $m$ between 0 and 1. Numerical estimates of the the characteristic multipliers show that these periodic orbits are linearly stability when $0.54\leq m\leq 1$, and are linearly unstable when $0<m\leq0.53$.Comment: 6 figure

Spillover of interpersonal conflicts from work into nonwork: A daily diary study

This study among a heterogeneous sample of employees expands the Job-Demands (JD-R) theory by examining how interpersonal conflicts at work -task and relationship conflictspillover into the non-work domain on a daily basis. We hypothesized that daily personal resources can buffer the daily negative spillover of interpersonal conflicts from work into the non-work domain. A total of 113 employees (N = 565 occasions) filled in a daily diary questionnaire in the evening before bedtime over five consecutive working days. Results of multi-level analysis showed that the presence of daily personal resources is essential in order to buffer the spillover of interpersonal conflict at work to the non-work domain. Specifically, on days that employees were not very optimistic or resilient, interpersonal conflicts resulted in higher strain-based work-life conflict experiences. These findings contribute to the JD-R theory and show how the unfavorable effects of daily interpersonal conflicts in the work domain may be avoided in the non-work domain through enhancing personal resources. We discuss the implications for theory and practice

A contingency analysis of precarious organizational temporariness

This paper extends our current understanding of organizational temporariness. The life of a temporary British trade union branch established to recruit Eastern European migrant workers reveals ‘precarious temporariness’, which is less predictable than the ‘planned temporariness’ typically portrayed in the literature. This different type of temporariness was associated with four key contingencies affecting the branch: dispersed governance, bottom-up initiatives, uncertain resourcing, and an effectuation logic. Analysis of the case extends our existing understanding of organizational temporariness and points to an extension of existing theorizing by highlighting the contingent nature of temporariness. The broader managerial implication of the findings is that for projects facing contingencies of the kind studied, the conventional linear approach of target setting and performance management will be less effective than an ongoing process of communication and consultation

An Ionophore‐Based Anion‐Selective Optode Printed on Cellulose Paper

A general anion‐sensing platform is reported based on a portable and cost‐effective ion‐selective optode and a smartphone detector equipped with a color analysis app. In contrast to traditional anion‐selective optodes using a hydrophobic polymer and/or plasticizer to dissolve hydrophobic sensing elements, the new optode relies on hydrophilic cellulose paper. The anion ionophore and a lipophilic pH indicator are inkjet‐printed and adsorbed on paper and form a “dry” hydrophobic sensing layer. Porous cellulose sheets also allow the sensing site to be modified with dried buffer that prevents any sample pH dependence of the observed color change. A highly selective fluoride optode using an AlIII‐porphyrin ionophore is examined as an initial example of this new anion sensing platform for measurements of fluoride levels in drinking water samples. Apart from Lewis acid–base recognition, hydrogen bonding recognition is also compatible with this sensing platform.Auf Cellulose‐Papier als Substrat wurden ein lipophiler Anionophor und ein pH‐Indikatorfarbstoff adsorbiert, um einen heterogenen Anionensensor mit Anion‐Proton‐Coextraktionsmechanismus zu erhalten. Dieses System eignet sich auch für die Adsorption eines Puffersalzes zur Einstellung des pH‐Werts der Probe, um pH‐abhängige optische Antworten auszuschließen.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138259/1/ange201706147-sup-0001-misc_information.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138259/2/ange201706147.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138259/3/ange201706147_am.pd

Aneuploidy in stem cells

Stem cells hold enormous promise for regenerative medicine as well as for engineering of model systems to study diseases and develop new drugs. The discovery of protocols that allow for generating induced pluripotent stem cells (IPSCs) from somatic cells has brought this promise steps closer to reality. However, as somatic cells might have accumulated various chromosomal abnormalities, including aneuploidies throughout their lives, the resulting IPSCs might no longer carry the perfect blueprint for the tissue to be generated, or worse, become at risk of adopting a malignant fate. In this review, we discuss the contribution of aneuploidy to healthy tissues and how aneuploidy can lead to disease. Furthermore, we review the differences between how somatic cells and stem cells respond to aneuploidy

Surface ocean-lower atmosphere study: Scientific synthesis and contribution to Earth system science

The domain of the surface ocean and lower atmosphere is a complex, highly dynamic component of the Earth system. Better understanding of the physics and biogeochemistry of the air-sea interface and the processes that control the exchange of mass and energy across that boundary define the scope of the Surface Ocean-Lower Atmosphere Study (SOLAS) project. The scientific questions driving SOLAS research, as laid out in the SOLAS Science Plan and Implementation Strategy for the period 2004-2014, are highly challenging, inherently multidisciplinary and broad. During that decade, SOLAS has significantly advanced our knowledge. Discoveries related to the physics of exchange, global trace gas budgets and atmospheric chemistry, the CLAW hypothesis (named after its authors, Charlson, Lovelock, Andreae and Warren), and the influence of nutrients and ocean productivity on important biogeochemical cycles, have substantially changed our views of how the Earth system works and revealed knowledge gaps in our understanding. As such SOLAS has been instrumental in contributing to the International Geosphere Biosphere Programme (IGBP) mission of identification and assessment of risks posed to society and ecosystems by major changes in the Earth́s biological, chemical and physical cycles and processes during the Anthropocene epoch. SOLAS is a bottom-up organization, whose scientific priorities evolve in response to scientific developments and community needs, which has led to the launch of a new 10-year phase. SOLAS (2015–2025) will focus on five core science themes that will provide a scientific basis for understanding and projecting future environmental change and for developing tools to inform societal decision-making