356 research outputs found

    Mathematical models of bipolar disorder

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    We use limit cycle oscillators to model bipolar II disorder, which is characterized by alternating hypomanic and depressive episodes and afflicts about 1% of the United States adult population. We consider two non-linear oscillator models of a single bipolar patient. In both frameworks, we begin with an untreated individual and examine the mathematical effects and resulting biological consequences of treatment. We also briefly consider the dynamics of interacting bipolar II individuals using weakly-coupled, weakly-damped harmonic oscillators. We discuss how the proposed models can be used as a framework for refined models that incorporate additional biological data. We conclude with a discussion of possible generalizations of our work, as there are several biologically-motivated extensions that can be readily incorporated into the series of models presented here

    Inheritance of Resistance to Common Bacterial Blight in Four Tepary Bean Lines

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    High levels of resistance to common bacterial blight caused by Xanthomonas campestris pv. phaseoli (Smith) Dye (Xcp) have been observed for tepary bean (Phaseolus acutifolius A. Gray var. latifolius Freeman). However, the inheritance of resistance from this source is unknown for many lines. The inheritance of common bacterial blight resistance was studied in four tepary bean lines crossed with the susceptible tepary bean MEX-114. Progenies were inoculated with a single Xcp strain 484a. Segregation ratios in the F2 generation suggested that resistance in Neb-T-6-s and PI 321637-s was governed by one dominant gene, and Neb T-8a-s had two dominant genes with complementary effects. These hypotheses for inheritance of resistance were supported by various combinations of F1, F3, BC1Pn segregation data in all lines except PI 321637-s where an additional minor-effect gene with recessive inheritance was indicated. Generation means analyses corroborated that multiple resistance genes were present in PI 321638-s. Lack of segregation for susceptibility among testcrosses for allelism between Neb-T-6-s/PI 321637-s, Neb-T-6-s/Neb-T-8a-s, PI 321637-s/Neb-T- 8a-s, and PI 321637-s/PI 321638-s, suggested that one or more loci conditioning resistance to common bacterial blight were in common across the four tepary lines

    Pinto Beans (\u3ci\u3ePhaseolus vulgaris\u3c/i\u3e L.) as a Functional Food: Implications on Human Health

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    Most foods are considered functional in terms of providing nutrients and energy to sustain daily life, but dietary systems that are capable of preventing or remediating a stressed or diseased state are classified as functional foods. Dry beans (Phaseolus vulgaris L.) contain high levels of chemically diverse components (phenols, resistance starch, vitamins, fructooligosaccharides) that have shown to protect against such conditions as oxidative stress, cardiovascular disease, diabetes, metabolic syndrome, and many types of cancer, thereby positioning this legume as an excellent functional food. Moreover, the United States has a rich dry bean history and is currently a top producer of dry beans in the world with pinto beans accounting for the vast majority. Despite these attributes, dry bean consumption in the US remains relatively low. Therefore, the objective of this manuscript is to review dry beans as an important US agricultural crop and as functional food for the present age with an emphasis on pinto beans

    Specific Genomic Regions in Common Bean Condition Resistance to Multiple Pathogens

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    A genetic linkage map of 170 RAPD markers mapped across 79 recombinant inbred lines (Dorado and XAN-176) reveal genomic regions that condition multiple disease resistance to fungal (Ashy Stem Blight‚ÄĒMacrophomina phaseolina), viral (bean golden mosaic virus‚ÄĒ BGMV), and bacterial (common bacterial blight‚ÄĒXanthomonas campestris pv. phaseoli) pathogens of common bean (Phaseolus vulgaris). A genomic site on linkage group US-1 had a major effect, explaining 18%, 34%, and 40% of the variation in phenotypic reaction to ashy stem blight, BGMV, and common bacterial blight disease, respectively. Adjacent to this region was a QTL conditioning 23% of the variation in reaction to another fungal pathogen, web blight (Thanatephorus cucumeris). A second genomic site on linkage group US-1 had minor affect on multiple resistance expression to the same fungal (15%), viral (15%), and bacterial (10%) pathogens. It is unknown whether these specific genomic regions represent a series of linked QTL affecting resistance to each disease separately or an individual locus with pleiotropic effect against all three pathogens

    Inheritance and QTL Analysis of Field Resistance to Ashy Stem Blight in Common Bean

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    Ashy stem blight [caused by Macrophomina phaseolina (Tassi) Goid.] can be a serious disease of common bean (Phaseolus vulgaris L.) under drought and high temperature conditions in some regions. The mode of inheritance of valuable sources of resistance is lacking. We studied inheritance of field resistance to ashy stem blight in a recombinant inbred population (’Dorado’ × XAN 176) consisting of 119 F5:7 recombinant inbred lines (RILs) tested in replicated experiments across 2 yr. A score from 1 to 9 (no disease to severe disease) was used to measure disease reaction. Moderate HNs (0.53 and 0.57) and near-normal frequency distribution of RILs for mean disease score each year indicated a lack of discrete segregation classes. The phenotypic variation across a subgroup composed of 79 RILs was further investigated with 165 randomly amplified polymorphic DNA (RAPD) markers by one-way analyses of variance and interval mapping. Five quantitative trait loci (QTL), explaining 19, 15, 15, 13, and 13% of the phenotypic variation for disease score, were detected in 1993. Three of these QTL, explaining 15,12, and 12% of the variation in disease reaction, were detected in 1994. Multiple QTL regression models (P \u3c 0.01) explained up to 47% (four loci) of the phenotypic variation for disease score in 1993 and 28% (three loci) in 1994. The five QTL, all derived from XAN 176, generally showed additive effects. These QTL-linked RAPD markers may prove useful for indirect selection of field resistance to ashy stem blight derived from XAN 176

    The challenges of containing SARS-CoV-2 via test-trace-and-isolate

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    Without a cure, vaccine, or proven long-term immunity against SARS-CoV-2, test-trace-and-isolate (TTI) strategies present a promising tool to contain the viral spread. For any TTI strategy, however, a major challenge arises from pre- and asymptomatic transmission as well as TTI-avoiders, which contribute to hidden, unnoticed infection chains. In our semi-analytical model, we identified two distinct tipping points between controlled and uncontrolled spreading: one, at which the behavior-driven reproduction number of the hidden infections becomes too large to be compensated by the available TTI capabilities, and one at which the number of new infections starts to exceed the tracing capacity, causing a self-accelerating spread. We investigated how these tipping points depend on realistic limitations like limited cooperativity, missing contacts, and imperfect isolation, finding that TTI is likely not sufficient to contain the natural spread of SARS-CoV-2. Therefore, complementary measures like reduced physical contacts and improved hygiene probably remain necessary

    El acceso a los servicios de salud bucodental para la poblaci√≥n adulta mayor en la red hospitalaria p√ļblica de Medell√≠n (Colombia)

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    Antecedentes/Objetivos: La poblaci√≥n adulta mayor es un grupo poblacional significativo teniendo en cuenta los cambios demogr√°ficos de las √ļltimas d√©cadas. En el pa√≠s y en la ciudad de Medell√≠n, este grupo presenta alta vulnerabilidad social, as√≠ mismo se observan necesidades en salud bucal, descritas en los estudios nacionales y regionales en el tema. Aunque se han realizado investigaciones que tratan de identificar determinantes que afectan el acceso y la utilizaci√≥n de los servicios de salud, los estudios en salud bucal son m√°s escasos y en especial en la poblaci√≥n adulta mayor. Objetivo: identificar barreras y facilitadores de acceso a los servicios de salud bucal en poblaci√≥n adulta mayor atendida en la red hospitalaria p√ļblica de Medell√≠n desde la perspectiva del personal de salud. M√©todos: Estudio cualitativo. Se realizaron 34 entrevistas semiestructuradas en personal que presta servicios de salud en la red Metrosalud de Medell√≠n. Se identificaron barreras y facilitadores seg√ļn el modelo de Tanahashi sobre cobertura en los servicios de salud a trav√©s de 4 categor√≠as: disponibilidad (D), accesibilidad (A), aceptabilidad (P) y contacto con el servicio (C). Se utiliz√≥ la herramienta inform√°tica AtlasTi. Resultados: Se identificaron barreras relacionadas con: dificultades en la implementaci√≥n de pol√≠ticas sociales debido a que la salud bucal no es una prioridad; se han priorizado otras poblaciones para dar atenci√≥n en salud bucal y existe insuficiente recurso humano para prestar los servicios de salud (D); la situaci√≥n de discapacidad de los adultos mayores (A); aspectos educativos, culturales y de g√©nero (P); y la crisis del sector salud como una barrera estructural del sistema (C). En cuanto a los facilitadores se mencionan: la existencia de programas que facilitan la demanda inducida a programas de salud bucal y de mecanismos para hacer valer los derechos en salud a trav√©s de instancias gubernamentales y otras (D); la ubicaci√≥n de las unidades y centros de salud en zonas de f√°cil acceso (A); la capacidad de los profesionales para atender esta poblaci√≥n (P) y la articulaci√≥n de la odontolog√≠a con otras √°reas (C). Conclusiones: Se identificaron determinantes que afectan el acceso a servicios sanitarios en la poblaci√≥n adulta mayor, por lo que se requieren estrategias para mejorar la calidad de la atenci√≥n en salud bucal en este grupo socialmente vulnerable.E.S.E Metrosalud. Medell√≠n (C√≥digo: C02-E11-L3-01)

    Tropical Forages ‚Äď Herramienta de Selecci√≥n

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    Tropical forages selection tool

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