Reproduction et croissance de BAIRDIELLA RONCHUS (Poisson SCIANIDAE) dans les mangroves de Guadeloupe (Antilles françaises)

BAIRDIELLA RONCHUS est un poisson sédentaire fréquent dans les mangroves de Guadeloupe. La population a été suivie durant les années 1979 et 1980, grâce à un échantillonnage mensuel des juvéniles et des adultes à la "capéchade" et des alevins à la roténone. L'évolution chronologique du R.G.S., des stades de maturité sexuelle et du stock d'alevins ont permis de mettre en évidence une période de reproduction s'étalant de mars à octobre et présentant trois pics d'activité reproductrice maximale, en mars en mai puis en septembre-octobre. L'étude de la croissance montre que cette espèce a une longévité très courte, excédant rarement 2 ans. La longue période de reproduction compense cette faible longévité pour permettre à l'espèce de se maintenir dans une lagune tropicale particulièrement isolée où les conditions peuvent devenir très contraignantes. (Résumé d'auteur

Increasing Risk: Dynamic Mean-Preserving Spreads

We extend the celebrated Rothschild and Stiglitz (1970) definition of Mean-Preserving Spreads to a dynamic framework. We adapt the original integral conditions to transition probability densities, and give sufficient conditions for their satisfaction. We then prove that a specific nonlinear scalar diffusion process, super-diffusive ballistic noise, is the unique process that satisfies the integral conditions among a broad class of processes. This process can be generated by a random superposition of linear Markov processes with constant drifts. This exceptionally simple representation enables us to systematically revisit, by means of the properties of Dynamic Mean-Preserving Spreads, four workhorse economic models originally based on White Gaussian Noise

Patient Perception of Privacy and the Role of Electronic Medical Records

In order to better manage patient records, hospitals and health care settings across the nation have begun to implement electronic medical record systems (EMR). The purpose of this transition is to reduce excessive amounts of paper, to decrease administrative costs, and to increase the overall quality of care. With the implementation of the EMR, relationships between physicians and their patients have the potential to change. Research has shown that patient perceptions are changing regarding confidentiality, trust, and privacy in the doctor-patient relationship because of patient medical records being stored electronically as opposed to being locked away in a file cabinet. Building on these findings, I analyze in-depth interviews of patients (N=44) to explore patient perceptions of EMRs and Privacy. The purpose of this research is to discover how patients perceive EMR, how they perceive privacy, and how they think the EMR plays a role in that privacy perception. I found two types of trust that have arisen due to EMR implementation, interpersonal trust and institutional trust. These types of trust are involved with providing the foundation for the formation of privacy perceptions. When patients are not concerned with the inappropriate exposure of their personal health information and perceive that the privacy of their records stored in the EMR is being adequately protected, they are much more likely to perceive trust and privacy with their physician and/or within their health care setting, and will be more likely to disclose their personal health information, which will lead to better patient care

Well-Distributed Sequences: Number Theory, Optimal Transport, and Potential Theory

The purpose of this dissertation will be to examine various ways of measuring how uniformly distributed a sequence of points on compact manifolds and finite combinatorial graphs can be, providing bounds and novel explicit algorithms to pick extremely uniform points, as well as connecting disparate branches of mathematics such as Number Theory and Optimal Transport. Chapter 1 sets the stage by introducing some of the fundamental ideas and results that will be used consistently throughout the thesis: we develop and establish Weyl\u27s Theorem, the definition of discrepancy, LeVeque\u27s Inequality, the Erdős-Turán Inequality, Koksma-Hlawka Inequality, and Schmidt\u27s Theorem about Irregularities of Distribution. Chapter 2 introduces the Monge-Kantorovich transport problem with special emphasis on the Benamou-Brenier Formula (from 2000) and Peyre\u27s inequality (from 2018). Chapter 3 explores Peyre\u27s Inequality in further depth, considering how specific bounds on the Wasserstein distance between a point measure and the uniform measure may be obtained using it, in particular in terms of the Green\u27s function of the Laplacian on a manifold. We also show how a smoothing procedure can be applied by propagating the heat equation on probability mass in order to get stronger bounds on transport distance using well-known properties of the heat equation. In Chapter 4, we turn to the primary question of the thesis: how to select points on a space which are as uniformly distributed as possible. We consider various diverse approaches one might attempt: an ergodic approach iterating functions with good mixing properties; a dyadic approach introduced in a 1975 theorem of Kakutani on proportional splittings on intervals; and a completely novel potential theoretic approach, assigning energy to point configurations and greedily minimizing the total potential arising from pair-wise point interactions. Such energy minimization questions are certainly not new, in the static setting--physicist Thomson posed the question of how to minimize the potential of electrons on a sphere as far back as 1904. However, a greedy approach to uniform distribution via energy minimization is novel, particularly through the lens of Wasserstein, and yields provably Wasserstein-optimal point sequences using the Green\u27s function of the Laplacian as our energy function on manifolds of dimension at least 3 (with dimension 2 losing at most a square root log factor from the optimal bound). We connect this to known results from Graham, Pausinger, and Proinov regarding best possible uniform bounds on the Wasserstein 2-distance of point sequences in the unit interval. We also present many open questions and conjectures on the optimal asymptotic bounds for total energy of point configurations and the growth of the total energy function as points are added, motivated by numerical investigations that display remarkably well-behaved qualities in the dynamical system induced by greedy minimization. In Chapter 5, we consider specific point sequences and bounds on the transport distance from the point measure they generate to the uniform measure. We provide provably optimal rates for the van der Corput sequence, the Kronecker sequence, regular grids and the measures induced by quadratic residues in a field of prime order. We also prove an upper bound for higher degree monomial residues in fields of prime order, and conjecture this to be optimal. In Chapter 6, we consider numerical integration error bounds over Lipschitz functions, asking how closely we can estimate the integral of a function by averaging its values at finitely many points. This is a rather classical question that was answered completely by Bakhalov in 1959 and has since become a standard example (`the easiest case which is perfectly understood\u27). Somewhat surprisingly perhaps, we show that the result is not sharp and improve it in two ways: by refining the function space and by proving that these results can be true uniformly along a subsequence. These bounds refine existing results that were widely considered to be optimal, and we show the intimate connection between transport distance and integration error. Our results are new even for the classical discrete grid. In Chapter 7, we study the case of finite graphs--we show that the fundamental question underlying this thesis can also be meaningfully posed on finite graphs where it leads to a fascinating combinatorial problem. We show that the philosophy introduced in Chapter 4 can be meaningfully adapted and obtain a potential-theoretic algorithm that produces such a sequence on graphs. We show that, using spectral techniques, we are able to obtain empirically strong bounds on the 1-Wasserstein distance between measures on subsets of vertices and the uniform measure, which for graphs of large diameter are much stronger than the trivial diameter bound

Developing communities of commensal bacteria to enhance immune defences to infection

The microbiota is the collective term referring to the diverse range of microorganisms which colonise the human body and other forms of higher life. This complex and dynamic community contains trillions of bacteria and other microbes; it has evolved alongside the host and inhabits all environmentally exposed surfaces within the body. As a result, the microbiota plays a critical role in host health and disease. In particular, the microbiota has been shown to be invaluable for a normal functioning immune system, with disruption to the microbiota resulting in increased susceptibility to pathogenic infection, as well as a multitude of inflammatory or autoimmune diseases. Microbiota-mediated regulation of the innate immune system is facilitated through the production of pattern recognition receptor (PRR) ligands and short-chain fatty acids (SCFAs). While both mechanisms of immune regulation are well-studied independently, the combine effect of these two pathways is far less well understood, despite occurring constantly during homeostasis. In this thesis, we show that the effect of PRR ligands and SCFAs on macrophages in isolation is distinct compared to their combined effect. We demonstrate that SCFAs modulate cytokine production induced by PRR activation, resulting from co-stimulation of macrophages with a wide range of commensal bacteria and different SCFAs. These SCFAs elicit either a pro- or anti-inflammatory effect depending on the sequential order of treatments. We also show that stimulation of PRRs by certain commensal bacteria is able to rescue macrophages from the cytotoxic concentrations of SCFAs, found within the host. Finally, using a Clostridium difficile infection (CDI) mouse model, we demonstrate that a combination of SCFA treatment and commensal bacteria inoculation, significantly reduces C. difficile load and increases expression of the antimicrobial peptide Reg3γ, in comparison to each treatment in isolation. The work outlined in this thesis provides a foundation for novel microbiome-based therapeutics, which can harness the combined potential of both PRR- and SCFA-mediated immune regulation, to enhance immune defences to infection.Open Acces

Anytime, Anyday, Anywhere

https://digitalcommons.library.umaine.edu/mmb-vp/4948/thumbnail.jp

The Need for a Spiritual Reboot in the Youth of Great Commission Church

The decline of the youth attendance is evident in many Protestant churches. This research paper examined forty-three young believers from three Haitian Baptist churches, respectively, located in Brooklyn, Queens, and the Bronx. These data results help develop a suitable spiritual program that includes the six key influencing factors for spiritual growth: discipleship, mentoring, parental influence, church attendance, personal devotion, and ministerial involvement. This spiritual program was tested on a small group of young people from Great Commission Church in Queens. This research uses a mixed-method methodology, which is a combination of qualitative and quantitative methods to analyze the data. The results show that parental influence can help Haitian youth attend church, but it does not encourage discipleship, mentorship, and ministerial involvement in the church. Further studies should aim at understanding the extent of parental involvement needed to encourage Haitian youth to be involved in the church\u27s ministries