A bijection between unicellular and bicellular maps

In this paper we present a combinatorial proof of a relation between the generating functions of unicellular and bicellular maps. This relation is a consequence of the Schwinger-Dyson equation of matrix theory. Alternatively it can be proved using representation theory of the symmetric group. Here we give a bijective proof by rewiring unicellular maps of topological genus $(g+1)$ into bicellular maps of genus $g$ and pairs of unicellular maps of lower topological genera. Our result has immediate consequences for the folding of RNA interaction structures, since the time complexity of folding the transformed structure is $O((n+m)^5)$, where $n,m$ are the lengths of the respective backbones, while the folding of the original structure has $O(n^6)$ time complexity, where $n$ is the length of the longer sequence.Comment: 18 pages, 13 figure

Global Issue of Clean Water as it Impacts Occupation

The purpose of this position paper is to explore the global impact of the lack or limited access to clean water on occupational engagement. The majority of the developed world has access to clean water, however, an alarming number of individuals do not have access to s governs, and impedes occupational engagement of millions globally. In order to enforce occupational justice, afforded from clean water, on a global scale, a fueling passion for change must be experienced by a collaborative force in a focused effort. Ultimately, access to clean water should be a basic human right propagated to all

A Review and New Framework for Instructional Design Practice Variation Research

This article reviews practice variation in the field of instructional design. First, it compares instructional designer practice as reported or observed in several classic research studies. This analysis is framed by the standards established by the IBSTPI competencies for planning and analysis, design and development, implementation and management. Although no certain causal linkages exist, we briefly review some of the reasons posited in the literature to explain ID practice variation (i.e. lack of time and resources, control in decision-making, the designer’s perception of a task, underlying philosophical beliefs, and designer expertise). Limitations of the literature-base are explored, followed by a proposal for an alternative view of ID practice variation and recommendations

Popular Culture as a Lens on Legal Professionalism

Why use art to teach lawyering?\u27 Despite divergences in method and intention, the two disciplines overlap. If the prevalence of lawyers in movies, television, literature, and even humor means anything, popular culture remains fascinated with lawyers. Our practices, our ethics, and our professional personae serve as a mine for image and narrative, a target for cultural critique, and a catalyst for expression. Not surprisingly, images of lawyers in cartoons, film, television, and literature offer unique opportunities to teach and explore professionalism. The proliferation of lawyer images in popular culture provides an array of material ranging from career choice to particular actions and behavior. This material elicits powerful responses about the morality, purpose, role, and identity of lawyers, in addition to traditional questions of legal ethics. The responses prompt students to reflect on career choice, professional persona in the legal world, and their development as human beings within a web of professional commitments. This Article argues that the cultural images of lawyering provide opportunities for teaching professionalism that go well beyond the teaching of ethical rules using hypothetical facts. We contend that use of different media allows teachers to chart the broad middle ground between disciplinary minima and aspirational maxima-the map of realistic professional practice. This ground includes both rule- and conduct-based ideas ofprofessionalism: careful role definition; responsible practice management; appropriate balance between public and private commitments; and concerns over manners, dress, and work ethic. The middle ground also includes less traditional content, discussion of which brings students to appreciate the subjective disciplines of lawyering. The subjective dimension includes the feel of lawyering for the practitioner: the psychic demands of an active, fully engaged practice. It also includes the subjective experience of the clients who use lawyers, as well as the complex interweaving of subjective and external factors in the situations in which lawyers are called to act. Using cultural representations of lawyers thus expands the notion of professionalism outside the bounds of the codified professional rules of conduct. One professor of ethics and professionalism refers to the examination of the varying layers of legal work as involving macro and micro contexts. We accept this distinction, and extend it: the rules of ethics provide a micro-context, around which popular media provide a macro context within which to appraise a different (and fuller) notion of professionalism. What renders the use of media unique is its tendency to prompt immediate imaginative experience and assessment of the various dimensions of professionalism. Through a well-chosen excerpt, one can consider both what the rules of ethics require alongside discussions of the moral complexity, emotional content, or even spiritual challenge posed by the situation. From these conversations, students can emerge with their language and awareness enlarged to include a richer and more reflective vision of their own identities as lawyers. Our argument proceeds in three phases. First, we review widespread notions of professionalism, illustrating and explicating our notion of professionalism as occupying the middle ground between discipline and aspiration. Second, we provide examples of teaching plans in which we have used different media, including examples of cartoons, movies, and short fiction as vehicles for teaching. Finally, we appraise the common challenges and objections to using the arts for these purposes; while law students form our first and most immediate pool of critics, these objections may have also occurred to others who have used the arts in this way. We recognize that our approach builds on the enthusiastic use of fictional representation in many modem law school ethics classes. We do not criticize, but rather seek to expand the range of what a teacher can do by using the arts in this way. We also hope to suggest the richness and power of conversations with students in which the traditional focus of classes on professionalism intersects with the more open-ended, expressive concerns of art

Identification of novel antimicrobial resistance genes from microbiota on retail spinach

BackgroundDrug resistance genes and their mobile genetic elements are frequently identified from environmental saprophytic organisms. It is widely accepted that the use of antibiotics in animal husbandry selects for drug resistant microorganisms, which are then spread from the farm environment to humans through the consumption of contaminated food products. We wished to identify novel drug resistance genes from microbial communities on retail food products. Here, we chose to study the microbial communities on retail spinach because it is commonly eaten raw and has previously been associated with outbreaks of bacterial infections.ResultsWe created metagenomic plasmid libraries from microbiota isolated from retail spinach samples. We identified five unique plasmids that increased resistance to antimicrobial drugs in the E. coli host. These plasmids were identified in E. coli that grew on plates that contained ampicillin (pAMP), aztreonam (pAZT), ciprofloxacin (pCIP), trimethoprim (pTRM), and trimethoprim-sulfamethoxazole (pSXT). We identified open reading frames with similarity to known classes of drug resistance genes in the DNA inserts of all 5 plasmids. These drug resistance genes conferred resistance to fluoroquinolones, cephalosporins, and trimethoprim, which are classes of antimicrobial drugs frequently used to treat human Gram negative bacterial infections. These results show that novel drug resistance genes are found in microbiota on retail produce items.ConclusionsHere we show that microbiota of retail spinach contains DNA sequences previously unidentified as conferring antibiotic resistance. Many of these novel sequences show similarity to genes found in species of bacteria, which have previously been identified as commensal or saprophytic bacteria found on plants. We showed that these resistance genes are capable of conferring clinically relevant levels of resistance to antimicrobial agents. Food saprophytes may serve as an important reservoir for new drug-resistance determinants in human pathogens

Effectiveness of zinc supplementation on diarrhea and average daily gain in pre-weaned dairy calves: A double-blind, block-randomized, placebo-controlled clinical trial.

The objective of this clinical trial was to evaluate the effectiveness of zinc supplementation on diarrhea and average daily weight gain (ADG) in pre-weaned dairy calves. A total of 1,482 healthy Holstein heifer and bull calves from a large California dairy were enrolled at 24 to 48 hours of age until hutch exit at approximately 90 days of age. Calves were block-randomized by time to one of three treatments: 1) placebo, 2) zinc methionine (ZM), or 3) zinc sulfate (ZS) administered in milk once daily for 14 days. Serum total protein at enrollment and body weight at birth, treatment end, and hutch exit were measured. Fecal consistency was assessed daily for 28 days post-enrollment. For a random sample of 127 calves, serum zinc concentrations before and after treatment and a fecal antigen ELISA at diarrhea start and resolution for Escherichia coli K99, rotavirus, coronavirus, and Cryptosporidium parvum were performed. Linear regression showed that ZM-treated bull calves had 22 g increased ADG compared to placebo-treated bulls (P = 0.042). ZM-treated heifers had 9 g decreased ADG compared to placebo-treated heifers (P = 0.037), after adjusting for average birth weight. Sex-stratified models showed that high birth weight heifers treated with ZM gained more than placebo-treated heifers of the same birth weight, which suggests a dose-response effect rather than a true sex-specific effect of ZM on ADG. Cox regression showed that ZM and ZS-treated calves had a 14.7% (P = 0.015) and 13.9% (P = 0.022) reduced hazard of diarrhea, respectively, compared to placebo-treated calves. Calves supplemented for at least the first five days of diarrhea with ZM and ZS had a 21.4% (P = 0.027) and 13.0% (P = 0.040) increased hazard of cure from diarrhea, respectively, compared to placebo-treated calves. Logistic regression showed that the odds of microbiological cure at diarrhea resolution for rotavirus, C. parvum, or any single fecal pathogen was not different between treatment groups. Zinc supplementation delayed diarrhea and expedited diarrhea recovery in pre-weaned calves. Additionally, zinc improved weight gain differentially in bulls compared to heifers, indicating a research need for sex-specific dosing

A phase transition in energy-filtered RNA secondary structures

In this paper we study the effect of energy parameters on minimum free energy (mfe) RNA secondary structures. Employing a simplified combinatorial energy model, that is only dependent on the diagram representation and that is not sequence specific, we prove the following dichotomy result. Mfe structures derived via the Turner energy parameters contain only finitely many complex irreducible substructures and just minor parameter changes produce a class of mfe-structures that contain a large number of small irreducibles. We localize the exact point where the distribution of irreducibles experiences this phase transition from a discrete limit to a central limit distribution and subsequently put our result into the context of quantifying the effect of sparsification of the folding of these respective mfe-structures. We show that the sparsification of realistic mfe-structures leads to a constant time and space reduction and that the sparsifcation of the folding of structures with modified parameters leads to a linear time and space reduction. We furthermore identify the limit distribution at the phase transition as a Rayleigh distribution.Comment: 34 pages, 6 figure