Lüke and power residue sequence diffusers

Conventional Schroeder diffusers have been successfully used for many years. However, their frequency range is limited by the flat plate effect that occurs when all the wells radiate in phase. This occurs at harmonics of p times the design frequency f(0), where p is the small prime that is used to generate the structure. A typical diffuser, using p=7 and f(0)=500 Hz, has an upper frequency limit of only 3.5 kHz. Achieving a first flat plate frequency above 20 kHz requires a prime equal to at least 41 and results in diffusers that are too big to be practical in most applications. This paper suggests an alternative approach using number theoretic sequences that, although short in length, are based on large integers. Two new sequences, Type-II Luke and power residue, have this desired characteristic. They are investigated using both simple models and the more exact boundary element method. The results show the flat plate effect is moved to much higher frequencies as expected. For Luke sequences at certain frequencies, redirection rather than dispersion is achieved. Modulation techniques can be used to mitigate these problems. Power residue sequences perform the best, providing good diffusion and a flat plate frequency outside the audible range

In vivo analysis of NHPX reveals a novel nucleolar localization pathway involving a transient accumulation in splicing speckles

The NHPX protein is a nucleolar factor that binds directly to a conserved RNA target sequence found in nucleolar box C/D snoRNAs and in U4 snRNA. Using enhanced yellow fluorescent protein (EYFP)– and enhanced cyan fluorescent protein–NHPX fusions, we show here that NHPX is specifically accumulated in both nucleoli and Cajal bodies (CBs) in vivo. The fusion proteins display identical localization patterns and RNA binding specificities to the endogenous NHPX. Analysis of a HeLa cell line stably expressing EYFP–NHPX showed that the nucleolar accumulation of NHPX was preceded by its transient accumulation in splicing speckles. Only newly expressed NHPX accumulated in speckles, and the nucleolar pool of NHPX did not interchange with the pool in speckles, consistent with a unidirectional pathway. The transient accumulation of NHPX in speckles prior to nucleoli was observed in multiple cell lines, including primary cells that lack CBs. Inhibitor studies indicated that progression of newly expressed NHPX from speckles to nucleoli was dependent on RNA polymerase II transcription, but not on RNA polymerase I activity. The data show a specific temporal pathway involving the sequential and directed accumulation of NHPX in distinct subnuclear compartments, and define a novel mechanism for nucleolar localization

Deterrence through Strength: British Naval Power and Foreign Policyunder Pax Britannica

Historians have long argued about the true mechanism behind a ninety-year period of relative peace in Europe, a period that began with the end of the Napoleonic wars and became known as the Pax Britannica. Over the years critics have questioned both aspects of this term—whether the period was actually as peaceful as its title suggests and whether that peace really was, in large part, due to Great Britain’s overwhelming and imposing com- mercial, industrial, financial, and naval might

Am I a Feminist? Narrative fidelity in Chimamanda Ngozi Adichie’s \u27We Should All be Feminists\u27

ABSTRACT In this paper I analyze Chimamanda Ngozi Adichie, and her TED Talk based off her book, “We Should All be Feminists.” Adichie is a Nigerian woman who has firsthand experience with feminist issues of inequality and she serves as a speaker and activist for issues of feminism and beyond. She is a renowned author, activist, academic, and a feminist. In hearing of her personal experiences regarding inequality, I realized I am able to identify parallels between her experiences and the inequalities which I have faced despite our vastly different origin stories. The importance of her work as a feminist is emphasized in her rhetorical techniques, such as using personal narratives and public vocabulary to bring connection and a sense of equality to her audience. Adichie urges society to modify their actions in order to promote and normalize feminism in a positive light

Four Lessons That the U.S. Navy Must Learn from the Dreadnought Revolution

Early in the twentieth century the Royal Navy, the world’s dominant naval force, stood at the cusp of fundamental technological and strategic shifts—and failed, as an institution, to respond effectively to them. Why? What can the U.S. Navy, in a similar position today, learn from the experience

Evaluating Public Masking Mandates on COVID-19 Growth Rates in U.S. States

U.S. state governments have implemented numerous policies to help mitigate the spread of COVID-19. While there is strong biological evidence supporting the wearing of face masks or coverings in public spaces, the impact of public masking policies remains unclear. We aimed to evaluate how early versus delayed implementation of state-level public masking orders impacted subsequent COVID-19 growth rates. We defined “early” implementation as having a state-level mandate in place before September 1, 2020, the approximate start of the school-year. We defined COVID-19 growth rates as the relative increase in confirmed cases 7, 14, 21, 30, 45, 60-days after September 1. Primary analyses used targeted maximum likelihood estimation (TMLE) with Super Learner and considered a wide range of potential confounders to account for differences between states. In secondary analyses, we took an unadjusted approach and calculated the average COVID-19 growth rate among early-implementing states divided by the average COVID-19 growth rate among late-implementing states. At a national level, the expected growth rate after 14-days was 4%lower with early vs. delayed implementation (aRR: 0.96; 95%CI: 0.95-0.98). Associations did not plateau over time, but instead grew linearly. After 60-days, the expected growth rate was 16% lower with early vs. delayed implementation (aRR:0.84; 95%CI: 0.78-0.91). Unadjusted estimates were exaggerated (e.g. 60-day RR:0.72; 95%CI: 0.60-0.84). Sensitivity analyses varying the timing of the masking order yielded similar results. In both the short and long term, state-level public masking mandates were associated with lower COVID-19 growth rates. Given their low-cost and minimal (if any) impact on the economy, masking policies are promising public health strategies to mitigate further spread of COVID-19

Ethical Frameworks in Public Health Decision-Making: Defending a Value-Based and Pluralist Approach

A number of ethical frameworks have been proposed to support decision-making in public health and the evaluation of public health policy and practice. This is encouraging, since ethical considerations are of paramount importance in health policy. However, these frameworks have various deficiencies, in part because they incorporate substantial ethical positions. In this article, we discuss and criticise a framework developed by James Childress and Ruth Bernheim, which we consider to be the state of the art in the field. Their framework distinguishes aims, such as the promotion of public health, from constraints on the pursuit of those aims, such as the requirement to avoid limitations to liberty, or the requirement to be impartial. We show how this structure creates both theoretical and practical problems. We then go on to present and defend a more practical framework, one that is neutral in avoiding precommitment to particular values and how they ought to be weighted. We believe ethics is at the very heart of such weightings and our framework is developed to reflect this belief. It is therefore both pluralist and value-based. We compare our new framework to Childress and Bernheim’s and outline its advantages. It is justified by its impetus to consider a wide range of alternatives and its tendency to direct decisions towards the best alternatives, as well as by the information provided by the ranking of alternatives and transparent explication of the judgements that motivate this ranking. The new framework presented should be useful to decision-makers in public health, as well as being a means to stimulate further reflection on the role of ethics in public health. Keywords Decision-making Ethical frameworks Justification Public health Value pluralis

KRILLBASE: a circumpolar database of Antarctic krill and salp numerical densities, 1926-2016

Antarctic krill (Euphausia superba) and salps are major macroplankton contributors to Southern Ocean food webs and krill are also fished commercially. Managing this fishery sustainably, against a backdrop of rapid regional climate change, requires information on distribution and time trends. Many data on the abundance of both taxa have been obtained from net sampling surveys since 1926, but much of this is stored in national archives, sometimes only in notebooks. In order to make these important data accessible we have collated available abundance data (numerical density, no. m(-2)) of postlarval E. superba and salp individual (multiple species, and whether singly or in chains). These were combined into a central database, KRILLBASE, together with environmental information, standardisation and metadata. The aim is to provide a temporal-spatial data resource to support a variety of research such as biogeochemistry, autecology, higher predator foraging and food web modelling in addition to fisheries management and conservation. Previous versions of KRILLBASE have led to a series of papers since 2004 which illustrate some of the potential uses of this database. With increasing numbers of requests for these data we here provide an updated version of KRILLBASE that contains data from 15 194 net hauls, including 12 758 with krill abundance data and 9726 with salp abundance data. These data were collected by 10 nations and span 56 seasons in two epochs (1926-1939 and 1976-2016). Here, we illustrate the seasonal, inter-annual, regional and depth coverage of sampling, and provide both circumpolar-and regional-scale distribution maps. Krill abundance data have been standardised to accommodate variation in sampling methods, and we have presented these as well as the raw data. Information is provided on how to screen, interpret and use KRILLBASE to reduce artefacts in interpretation, with contact points for the main data providers