Power laws, Pareto distributions and Zipf's law

When the probability of measuring a particular value of some quantity varies inversely as a power of that value, the quantity is said to follow a power law, also known variously as Zipf's law or the Pareto distribution. Power laws appear widely in physics, biology, earth and planetary sciences, economics and finance, computer science, demography and the social sciences. For instance, the distributions of the sizes of cities, earthquakes, solar flares, moon craters, wars and people's personal fortunes all appear to follow power laws. The origin of power-law behaviour has been a topic of debate in the scientific community for more than a century. Here we review some of the empirical evidence for the existence of power-law forms and the theories proposed to explain them.Comment: 28 pages, 16 figures, minor corrections and additions in this versio

Strategies to Improve Employee Ethical Conduct in Health Care Organizations

Organizational leaders face challenges related to implementing ethical standards, which influence performance, organization sustainability, and culture. The purpose of this single case study was to explore ethics strategies that health care business leaders used to improve employees\u27 ethical conduct. Data were collected through face-to-face, semistructured interviews with a purposive sample of 7 business leaders of a health care organization located in central Georgia and a review of organization documents. The conceptual framework was Brady\u27s Janus-headed model of ethical theory. Using a priori coding during the data analysis process provided 3 thematic categories: policy strategies for the improvement of employee ethical conduct, ethics strategies used to address employee unethical conduct, and strategies to overcome barriers of strategy implementation. Themes that emerged from the data were accountability and responsibility, leadership development, escalating behaviors, and adapting to change. The findings from this study might contribute to social change by providing information about ethical strategies leaders used to improve employee ethical conduct, which can be used to influence individuals\u27 livelihood, stakeholders\u27 comfort level, and the well-being of the community

Effect of Structural Parameters on Superconductivity in Fluorine-Free LnFeAsO1-y (Ln=La,Nd)

The crystal structure of LnFeAsO$_{1-y}$ (Ln = La, Nd) has been studied by the powder neutron diffraction technique. The superconducting phase diagram of NdFeAsO$_{1-y}$ is established as a function of oxygen content which is determined by Rietveld refinement. The small As-Fe bond length suggests that As and Fe atoms are connected covalently. FeAs$_4$-tetrahedrons transform toward a regular shape with increasing oxygen deficiency. Superconducting transition temperatures seem to attain maximum values for regular FeAs$_4$-tetrahedrons

Infrared and microwaves at 5.8 GHz in a catalytic reactor

An improved micro-reactor cell for IR spectroscopic studies of heterogeneous catalysis was built around a 5.8 GHz microwave cavity. The reactor can operate at 20 bars and with conventional heating up to 720 K, with reactant gas flows velocities (GHSV) from 25 000 to 50 000 h−1. The temperature of the sample under microwave irradiation was measured by time resolved IR emission spectroscopy. The first experiment performed was the IR monitoring of the desorption of carbonates induced by irradiating an alumina sample by microwaves at 5.8 GHz

Uranium(III) coordination chemistry and oxidation in a flexible small-cavity macrocycle

U(III) complexes of the conformationally flexible, small-cavity macrocycle trans-calix[2]benzene[2]pyrrolide (L)2–, [U(L)X] (X = O-2,6-tBu2C6H3, N(SiMe3)2), have been synthesized from [U(L)BH4] and structurally characterized. These complexes show binding of the U(III) center in the bis(arene) pocket of the macrocycle, which flexes to accommodate the increase in the steric bulk of X, resulting in long U–X bonds to the ancillary ligands. Oxidation to the cationic U(IV) complex [U(L)X][B(C6F5)4] (X = BH4) results in ligand rearrangement to bind the smaller, harder cation in the bis(pyrrolide) pocket, in a conformation that has not been previously observed for (L)2–, with X located between the two ligand arene rings

The increase of the functional entropy of the human brain with age

We use entropy to characterize intrinsic ageing properties of the human brain. Analysis of fMRI data from a large dataset of individuals, using resting state BOLD signals, demonstrated that a functional entropy associated with brain activity increases with age. During an average lifespan, the entropy, which was calculated from a population of individuals, increased by approximately 0.1 bits, due to correlations in BOLD activity becoming more widely distributed. We attribute this to the number of excitatory neurons and the excitatory conductance decreasing with age. Incorporating these properties into a computational model leads to quantitatively similar results to the fMRI data. Our dataset involved males and females and we found significant differences between them. The entropy of males at birth was lower than that of females. However, the entropies of the two sexes increase at different rates, and intersect at approximately 50 years; after this age, males have a larger entropy

From the National to the Local: Issues of Trust and a Model For Community-Academic-Engagement

Inequities in health and health care in the United States have persisted for decades, and the impacts on equity from the COVID-19 pandemic were no exception. In addition to the disproportionate burden of the disease across various populations, the pandemic posed several challenges, which exacerbated these existing inequities. This has undoubtedly contributed to deeply rooted public mistrust in medical research and healthcare delivery, particularly among historically and structurally oppressed populations. In the summer of 2020, given the series of social injustices posed by the pandemic and highly publicized incidents of police brutality, notably the murder of George Floyd, the Association of American Medical Colleges (AAMC) enlisted the help of a national collaborative, the AAMC Collaborative for Health Equity: Act, Research, Generate Evidence (CHARGE) to establish a three-way partnership that would gather and prioritize community perspectives and lived experiences from multiple regions across the US on the role of academic medicals centers (AMCs) in advancing health and social justice. Given physical gathering constraints posed by the pandemic, virtual interviews were conducted with 30 racially and ethnically diverse community members across the country who expressed their views on how medical education, clinical care, and research could or did impact their health experiences. These interviews were framed within the context of the relationship between historically oppressed groups and the COVID-19 vaccine clinical trials underway. From the three-way partnership formed with the AAMC, AAMC CHARGE participants, and 30 community members from racially and ethnically diverse groups, qualitative methods provided lived experiences supporting other literature on the lack of trust between oppressed communities and AMCs. This led to the development of the Principles of Trustworthiness (PoT) toolkit, which features ten principles inspired by community members\u27 insights into how AMCs can demonstrate they are worthy of their community\u27s trust. In the end, the three-way partnership serves as a successful model for other national medical and health organizations to establish community engaged processes that elicit and prioritize lived experiences describing relationships between AMCs and oppressed communities

Silenced encounters: an affective history of accessing abortion in Alberta, 1969-1988

This thesis is an affective history of abortion as told through the memories from four individuals; two retired medical practitioners who sat on Therapeutic Abortion Committees (TACs) and two women who accessed abortion services in Alberta between 1969 and 1988. Further, my analysis of access to abortion focuses not only on the convoluted history of reproductive services in Alberta but also draws attention to the communities of affect that circulate between individual agents such as between the medical practitioner and the patient, the narrator and the interviewer, and also the dialogue that often ensues in casual encounters where the topic of abortion is discussed. Through focusing on the complex emotions that circulate within the four oral histories of abortion, I aim to challenge the binary of either grief or relief that is often equated to narratives of abortion

Exploration of bacterial community classes in major human habitats

BACKGROUND: Determining bacterial abundance variation is the first step in understanding bacterial similarity between individuals. Categorization of bacterial communities into groups or community classes is the subsequent step in describing microbial distribution based on abundance patterns. Here, we present an analysis of the groupings of bacterial communities in stool, nasal, skin, vaginal and oral habitats in a healthy cohort of 236 subjects from the Human Microbiome Project. RESULTS: We identify distinct community group patterns in the anterior nares, four skin sites, and vagina at the genus level. We also confirm three enterotypes previously identified in stools. We identify two clusters with low silhouette values in most oral sites, in which bacterial communities are more homogeneous. Subjects sharing a community class in one habitat do not necessarily share a community class in another, except in the three vaginal sites and the symmetric habitats of the left and right retroauricular creases. Demographic factors, including gender, age, and ethnicity, significantly influence community composition in several habitats. Community classes in the vagina, retroauricular crease and stool are stable over approximately 200 days. CONCLUSION: The community composition, association of demographic factors with community classes, and demonstration of community stability deepen our understanding of the variability and dynamics of human microbiomes. This also has significant implications for experimental designs that seek microbial correlations with clinical phenotypes