Dependence Among Spacings

In this paper, we study the dependence properties of spacings. It is proved that if X1,..., Xn are exchangeable random variables which are TP2 in pairs and their joint density is log-convex in each argument, then the spacings are MTP2 dependent. Next, we consider the case of independent but nonhomogeneous exponential random variables. It is shown that in this case, in general, the spacings are not MTP2 dependent. However, in the case of a single outlier when all except one parameters are equal, the spacings are shown to be MTP2 dependent and, hence, they are associated. A consequence of this result is that in this case, the variances of the order statistics are increasing. It is also proved that in the case of the multiple-outliers model, all consecutive pairs of spacings are TP2 dependent

Hartman-Grobman Theorems along Hyperbolic Stationary Trajectories

We extend the Hartman-Grobman theorems on discrete random dynamical systems (RDS), proved in [7], in two directions: For continuous RDS and for hyperbolic stationary trajectories. In this last case there exists a conjugacy between traveling neighbourhoods of trajectories and neighbourhoods of the origin in the corresponding tangent bundle. We present applications to deterministic dynamical systems

Masticatory loading and soft-tissue plasticity in the mammalian circumorbital region

Abstract only availableMasticatory loading is the key to understanding the plasticity or epigenetic responses of many of the soft and hard tissues of the mammalian skull. Diet-induced variation in the magnitude and/or frequency of masticatory loads influences the organization, functional adaptation and postnatal development of craniofacial systems. While experimental work exists concerning masticatory stress as a determinant of maxillomandibular form, similar research concerning the mammalian circumorbital region of soft-tissue structures remains sparse. Indeed, controversy remains over the function of the circumorbital region, specifically whether the postorbital region in primates and other mammals is responsive to biomechanical loading. This hinders our understanding of evolutionary transformations during primate origins, where the earliest primates evolved a bony postorbital bar from an ancestor with a soft-tissue structure along the lateral orbital margin. To fill this gap, we examined the postorbital microanatomy of white rabbits (Oryctolagus cuniculus). Rabbits exhibit a masticatory complex and feeding behaviors like primates, yet retain a primitive circumorbital region similar to their common ancestor. To address the plasticity and function of soft tissues of the lateral orbital wall, three cohorts of 10 rabbits each were raised from weaning (1 month old) to adulthood (6 months old) on diets of different mechanical properties (under-use, control, over-use). Once sacrificed, tissues were collected from the left lateral orbital wall. Dissections revealed that, rather than the anticipated postorbital ligament, rabbits instead exhibit fibrocartilage. Samples were analyzed histologically and immunohistochemically for general anatomy, fibril architecture, collagen expression/organization, and protein abundance using Western Blot analysis. Preliminary data suggests that collagen fibers are aligned differently, with an overexpression of collagen in the over-use dietary cohort versus both the control and under-use groups. In sum, these experimental findings suggest that the postorbital fibrocartilage is mechanically responsive, which contrasts with the non-masticatory nature of bony elements in the circumorbital region.Life Sciences Undergraduate Research Opportunity Progra

Dynamics of pfcrt alleles CVMNK and CVIET in chloroquine-treated Sudanese patients infected with Plasmodium falciparum

BACKGROUND: Parasite resistance to the anti-malarial drug chloroquine is common in eastern Sudan. Dynamic within-host changes in the relative abundance of both sensitive and resistant Plasmodium falciparum parasites were examined in a cohort of chloroquine-treated patients presenting with uncomplicated falciparum malaria, using a novel allele-specific quantitative approach. METHODS: Treatment outcomes were determined for 93 patients of all ages in a per protocol cohort using a modified 14-day WHO protocol. Parasite DNA samples at days 0, 1, 2, 3, 7 and 14 following treatment were analysed using real-time quantitative PCR methods that distinguished resistant and sensitive genotypes at amino acids 72-76 of the pfcrt locus. RESULTS: Chloroquine treatment was not efficacious, and of 93 assessable patients, only 10 individuals (10.7%; 95% C.I. 4.34-17.2%) enjoyed an adequate clinical and parasitological response. Resistant parasites with the haplotype CVIET at codons 72-76 of the pfcrt locus were dominant in the starting population. Chloroquine sensitive parasites with the haplotype CVMNK were detected in 19 individuals prior to treatment (20.43%; 95% C.I. 5.14-18.5%). In these patients, CQ treatment rapidly selected CVIET parasites, and this haplotype overwhelmingly dominated the parasite population in each individual by day 2 after treatment. CONCLUSIONS: Such rapid intra-host selection of particular genotypes after the introduction of drug will cause frequent misidentification of parasite genotypes present in the starting population. This will have a potentially serious confounding effect on clinical trials which employ PCR-corrected estimates of treatment failure, as resistant parasites below the detection threshold in the pre-treatment sample can be erroneously classified as "new" infections during follow-up, over-estimating drug efficacy

The equatorial West Pacific fresh pool at the end of the La Nina event in October/November 1996

The salinity, temperature and current distributions have been measured during the TROPAC cruise (Oct./Nov. 1996) at two sections, i.e. 143°E and 150°E, during the final phase of the 1995/1996 La Niña. The results present evidence that the fresh pool and the salinity front at its eastern boundary had moved far to the west, and that a barrier layer existed in that phase. The observed currents support the idea that advective processes play an essential role in creating the thermohaline structure during this ENSO phase. In relation with this process, it is found that the westward subduction mechanism of relatively dense eastern equatorial waters may apply during that phase

Patient Frailty: Key Considerations, Definitions and Practical Implications

By 2020, the elderly (≥65-year-old) world population is projected to exceed one billion individuals. This demographic megatrend has brought topics such as physiological age and frailty to the forefront of medical research efforts around the globe. The concept of frailty has evolved significantly since the mid-twentieth century. The outdated stereotype of a “thin, stooped, slow octogenarian” has transitioned to a more scientific and objective understanding of the problem. Still, a comprehensive and concise definition of “frailty” remains elusive. Until such a definition is firmly established and universally agreed upon, clinicians continue to rely on the somewhat subjective conceptual framework of today. In this chapter, the authors review key issues pertaining to clinical management of frail patients, including diagnosis/identification, preventive strategies, therapeutic approaches, and common pitfalls. The relationship between frailty, various domains of life, and functional status is also discussed. Finally, we will touch upon the concepts of end-of-life and goals of care, focusing on their relationship to frailty

Alternatively spliced transcripts and novel pseudogenes of the Plasmodium falciparum resistance-associated locus pfcrt detected in East African malaria patients.

OBJECTIVES: Polymorphisms in the lysosomal transporter encoded by the pfcrt gene directly impact on Plasmodium falciparum susceptibility to aminoquinolines. The Lys76Thr mutation is the critical change conferring chloroquine resistance in vitro and in vivo, but always occurs with additional non-synonymous changes in the pfcrt coding sequence. We sought to better describe pfcrt polymorphisms distal to codon 76. METHODS: Small-volume samples (≤ 500 μL) of parasite-infected blood collected directly from malaria patients presenting for treatment in Sudan and Tanzania were immediately preserved for RNA extraction. The pfcrt locus was amplified from cDNA preparations by nested PCR and sequenced directly to derive full-length mRNA sequences. RESULTS: In one of two sites in Sudan, two patients were found with an unorthodox spliced form of pfcrt mRNA in which two exons were skipped, but it was not possible to test for the presence of the putative protein products of these aberrant transcripts. Genomic DNA sequencing from dried blood spots collected in parallel confirmed the presence of spliced pfcrt pseudogenes in a minority of parasite isolates. Full-length cDNA from conventionally spliced mRNA molecules in all study sites demonstrated the existence of a variety of pfcrt haplotypes in East Africa, and thus provides evidence of intragenic recombination. CONCLUSIONS: The presence of pseudogenes, although unlikely to have any direct public health impact, may confound results obtained from simple genotyping methods that consider only codon 76 and the adjacent residues of pfcrt

The <i>Arabidopsis</i> NPF3 protein is a GA transporter

Gibberellins (GAs) are plant hormones that promote a wide range of developmental processes. While GA signalling is well understood, little is known about how GA is transported or how GA distribution is regulated. Here we utilize fluorescently labelled GAs (GA-Fl) to screen for Arabidopsis mutants deficient in GA transport. We show that the NPF3 transporter efficiently transports GA across cell membranes in vitro and GA-Fl in vivo. NPF3 is expressed in root endodermis and repressed by GA. NPF3 is targeted to the plasma membrane and subject to rapid BFA-dependent recycling. We show that abscisic acid (ABA), an antagonist of GA, is also transported by NPF3 in vitro. ABA promotes NPF3 expression and GA-Fl uptake in plants. On the basis of these results, we propose that GA distribution and activity in Arabidopsis is partly regulated by NPF3 acting as an influx carrier and that GA–ABA interaction may occur at the level of transport

Campagne océanographique FLUPAC à bord du N.O. l'ATALANTE 23 septembre au 29 octobre 1994. Recueil des données. Tome 1 : météo, courantologie, hydrologie, données de surface

La campagne FLUPAC du N.O. L'Atalante, qui s'est déroulée du 23 septembre au 29 octobre 1994, s'est placée dans le cadre du programme international JGOFS (JOINT GLOBAL OCEAN FLUX STUDY). Elle a comporté deux radiales et deux stations équatoriales de 6-7 jours. La première radiale, le long de 165°E, a parcouru la zone comprise entre 20°S et 6°N. La seconde s'est déroulée le long de l'équateur entre 167°E et 150°W. Les deux stations de longue durée ont eu lieu à O°-167°E et 0°-150°W. Elles ont été l'occasion d'études détaillées des flux impliqués dans le cycle du carbone de la couche superficielle (0-500 m). Le premier tome du recueil de données présente des résultats, sous forme de graphiques et de tableaux, des paramètres enregistrés en continu et de ceux de la sonde CTD. Les paramètres chimiques, la chlorophylle "a" et les observations en cytomètrie de flux obtenus sur l'eau de la "rosette" couplée à la sonde CTD, sont également présentés. (Résumé d'auteur