Minimax Estimation of Distances on a Surface and Minimax Manifold Learning in the Isometric-to-Convex Setting

We start by considering the problem of estimating intrinsic distances on a smooth surface. We show that sharper estimates can be obtained via a reconstruction of the surface, and discuss the use of the tangential Delaunay complex for that purpose. We further show that the resulting approximation rate is in fact optimal in an information-theoretic (minimax) sense. We then turn to manifold learning and argue that a variant of Isomap where the distances are instead computed on a reconstructed surface is minimax optimal for the problem of isometric manifold embedding

Supervising Embedding Algorithms Using the Stress

While classical scaling, just like principal component analysis, is parameter-free, most other methods for embedding multivariate data require the selection of one or several parameters. This tuning can be difficult due to the unsupervised nature of the situation. We propose a simple, almost obvious, approach to supervise the choice of tuning parameter(s): minimize a notion of stress. We substantiate this choice by reference to rigidity theory. We extend a result by Aspnes et al. (IEEE Mobile Computing, 2006), showing that general random geometric graphs are trilateration graphs with high probability. And we provide a stability result \`a la Anderson et al. (SIAM Discrete Mathematics, 2010). We illustrate this approach in the context of the MDS-MAP(P) algorithm of Shang and Ruml (IEEE INFOCOM, 2004). As a prototypical patch-stitching method, it requires the choice of patch size, and we use the stress to make that choice data-driven. In this context, we perform a number of experiments to illustrate the validity of using the stress as the basis for tuning parameter selection. In so doing, we uncover a bias-variance tradeoff, which is a phenomenon which may have been overlooked in the multidimensional scaling literature. By turning MDS-MAP(P) into a method for manifold learning, we obtain a local version of Isomap for which the minimization of the stress may also be used for parameter tuning

Comparative evaluation of pyrethroid insecticide formulations against Triatoma infestans (Klug): residual efficacy on four substrates

We investigated the residual efficacy of four insecticide formulations used in Chagas disease vector control campaigns: cyfluthrin 12.5% suspension concentrace (SC), lambda- cyhalothrin 10% wettable powder (WP), deltamethrin 2.5% SC, and 2.5% WP on four types of circular blocks of wood, straw with mud, straw with mud painted with lime, and mud containing 5% of cement. Three concentrations of these insecticides were tested: the LC90 (previously determined on filter paper), the double of the LC90, and the recommended operational dose. For each bioassay test, 15 third-stage nymphs of Triatoma infestans (Klug) (Hemiptera: Reduviidae) were exposed for 120 h to each treatment at 24 h, 30, 60, 90, and 180 days post-spraying. Mortality rates, moulting history and behaviour were recorded at 24, 48, 72, and 120 h of exposure. Mortality rates were highest during the first 30 days post-spraying. Highest mortality rates (above 50%) were observed for deltamethrin 2.5% SC and lambda-cyhalothrin 10% WP on wood blocks up to three months post-spraying. Mud was the substrate on which treatments showed lowest persistence, with the other two substrates showing intermediate residual efficacy of all treatments. During the first 30 days WP formulations were not as effective as SC flowable formulations but, overall in the longer term, WP gave grater mortality rates of T. infestans nymphs exposed at up to six months post-spraying. Porous surfaces, especially mud, showed most variability presumably due to absorption of the insecticide. In contrast the less porous surfaces (i.e. wood and lime-coated mud) kept mortality rates high for longer post-treatment, irrespective of the insecticide concentration used

Estudio exploratorio sobre las inferencias generadas por el texto de poesía religiosa, en los jóvenes universitarios de la carrera de comunicación social de la universidad politécnica salesiana de Guayaquil.

This study highlights the importance of inferences generated by religious poetry texts containing important moral and human subjectivity and cultural values in our society, there are currently lacking in the transmission of these values in all social institutions in Latin America, especially in the universities of the city of Guayaquil where compliance with the contents of the curriculum predominate. The study used the method of content analysis, getting to know the connection between poets and young readers, which generates significant for the life of university students inferences, even surpassing deeply to the music of reggaetón. Inferences produced by the young people surveyed are related to aspects related to the humanistic part of the subject especially to respect the ecological, sense of love in our relationships; as well as the integration between pain and love to overcome the trials of life, and finally achieved the connection between our cognitions somewhat subjective divine. We can conclude that the interaction between youth and religious poetry text provides useful knowledge to guide their lives.El presente trabajo es una investigación exploratoria cualitativa sobre las inferencias que se generan  a partir de la lectura de poesía religiosa, con la intensión de para rescatar y valorizar este género literario en la ciudad portuaria de Guayaquil. Planteándonos conocer que inferencia son producido luego de leer poesía religiosa guayaquileña, Se pudo determinar  por medio del análisis de contenido, que los jóvenes coinciden con el valor trasmitidos por los poetas en comparación  a la música de reggaetón, que no genera ningún tipo de inferencias en los participantes universitarios, las inferencias generadas por la poesía religiosa están relacionadas con la Vinculación de respeto ecológico; El sentido de amar en nuestras interrelaciones; Capacidad creativa para superar las adversidades de la vida con ayuda de los pares; como el equilibrio integrar del dolor y el amor para sobreponerse a las pruebas de la vida; y conexión cognitiva con lo divino

Characterization of <i>Aedes aegypti</i> innate-immune pathways that limit Chikungunya virus replication

Replication of arboviruses in their arthropod vectors is controlled by innate immune responses. The RNA sequence-specific break down mechanism, RNA interference (RNAi), has been shown to be an important innate antiviral response in mosquitoes. In addition, immune signaling pathways have been reported to mediate arbovirus infections in mosquitoes; namely the JAK/STAT, immune deficiency (IMD) and Toll pathways. Very little is known about these pathways in response to chikungunya virus (CHIKV) infection, a mosquito-borne alphavirus (Togaviridae) transmitted by aedine species to humans resulting in a febrile and arthralgic disease. In this study, the contribution of several innate immune responses to control CHIKV replication was investigated. In vitro experiments identified the RNAi pathway as a key antiviral pathway. CHIKV was shown to repress the activity of the Toll signaling pathway in vitro but neither JAK/STAT, IMD nor Toll pathways were found to mediate antiviral activities. In vivo data further confirmed our in vitro identification of the vital role of RNAi in antiviral defence. Taken together these results indicate a complex interaction between CHIKV replication and mosquito innate immune responses and demonstrate similarities as well as differences in the control of alphaviruses and other arboviruses by mosquito immune pathways

Bacillus amyloliquefaciens GA1 as a source of potent antibiotics and other secondary metabolites for biocontrol of plant pathogens

Phytopathogenic fungi affecting crop and post-harvested vegetables are a amajor threat to food production and food storage. To face these drawbacks, producers have become increasingly dependent on agrochemicals. However, intensive use of these compounds has led to the emergence of pathogen resistance and severe negative environmental impacts. There are also a number of plant diseases for which chemical solutions are ineffective or non-existent as well as an increasing demand by consumers for pesticide-free food. Thus, biological control through the use of natural antagonistic microorganisms has emerged as a promising alternative to chemical pesticides for more rational and safe crop management. RESULTS: The genome of the plant-associated B. amyloliquefaciens GA1 was sample sequenced. Several gene clusters involved in the synthesis of biocontrol agents were detected. Four gene clusters were shown to direct the synthesis of the cyclic lipopeptides surfactin, iturin A and fengycin as well as the iron-siderophore bacillibactin. Beside these non-ribosomaly synthetised peptides, three additional gene clusters directing the synthesis of the antibacterial polyketides macrolactin, bacillaene and difficidin were identified. Mass spectrometry analysis of culture supernatants led to the identification of these secondary metabolites, hence demonstrating that the corresponding biosynthetic gene clusters are functional in strain GA1. In addition, genes encoding enzymes involved in synthesis and export of the dipeptide antibiotic bacilysin were highlighted. However, only its chlorinated derivative, chlorotetaine, could be detected in culture supernatants. On the contrary, genes involved in ribosome-dependent synthesis of bacteriocin and other antibiotic peptides were not detected as compared to the reference strain B. amyloliquefaciens FZB42. CONCLUSION: The production of all of these antibiotic compounds highlights B. amyloliquefaciens GA1 as a good candidate for the development of biocontrol agents

Colación: equidad en la masa hereditaria en una sucesión testamentaria

Se ha planteado como objetivo explicar cómo el tercio de libre disponibilidad excluye a uno o más herederos forzosos en el actual Código Civil Peruano. La metodología se dio bajo el enfoque cualitativo, básica, realizando la validez de las entrevistas que se han realizado a profesionales del área jurídica expertos en Derecho de Familia y Civil Se ha concluido que un causante en vida cuando desea favorecer a uno o más herederos forzosos solo puede disponer libremente de su tercio de libre disponibilidad realizando la dispensa de colación, mediante la colación, se busca restablecer el desbalance al beneficiar a un heredero forzoso y excluir a los otros herederos forzosos. Asimismo, fue importante establecer la diferencia entre heredero y legatario para determinar si se tiene derecho o no a la colación, en vista que solo los herederos forzosos pueden interponer una demanda de colación. Finalmente, se desarrolla el tema del daño económico y moral que surge en la colación, pues quien la solicita no solo ve disminuida su herencia sino debe enfrentar a su familia, con la cual tiene vínculos afectivos, lo cual genera depresión y ansieda

New prenylated quinones from Peperomia galioides

Two new prenylated quinones, piperogalone and galopiperone, and a new prenylated dihydroquinone, hydropiperone, were isolated from #Peperomia galioides H.B.K (#Piperaceae). Hydropiperone exhibited potent antiparasitic activity against three species of #Leishmania$. (Résumé d'auteur

Multicenter study of patients' preferences and concerns regarding the origin of bone grafts utilized in dentistry

Purpose: bone graft materials can be obtained from the patient's own body (autologous graft), animals (xenograft), human cadavers (allograft) and synthetic materials (alloplastic bone graft). Patients may have ethical, religious or medical concerns about the origin of bone grafts, which could lead them to reject the use of certain types of bone graft in their treatments. The aim of this multicenter study, which surveyed patients from five university clinics in Portugal, France, Italy, Spain and Chile, was to analyze patients' opinions regarding the source of bone grafts. Patients and methods: a survey composed of ten questions was translated into local languages and validated. Patients were asked about the degree of acceptance/rejection of each graft and the reasons for rejection. A chi-squared test was used to analyze statistically significant differences. Results: three hundred thirty patients were surveyed. The grafts that elicited the highest percentage of refusal were allograft (40.4%), autologous bone graft from an extraoral donor site (34%) and xenograft (32.7%). The grafts with the lowest rate of refusal were alloplastic (6.3%) and autologous bone grafts from an intraoral donor site (24.5%). The main reason for autologous bone rejection was the fear of pain and discomfort, for xenograft it was the fear of disease transmission and the rejection of use of animals for human benefit, and for allograft it was ethical/moral motivations and the fear of disease transmission. Religious affiliation influenced patient's preferences. Conclusion: the origin of bone grafts is still conflictive for a high percentage of patients