2,909 research outputs found

    Understanding Perturbation in Aquatic Insect Communities under Multiple Stressor Threat

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    In the scientific literature, there is a considerable consensus that working toward evaluating multiple stressors is worthwhile. Unfortunately, our means to evaluate the combined effects of multiple stressors on species is limited. In agricultural systems, the relative threat posed to aquatic insect communities due to individual stressors (e.g., individual insecticides) is relatively well understood. However, understanding mixtures of pesticides, let alone the addition of complex and potentially interacting, natural gradients (e.g., nutrients and predation), is far harder. The objective of the following review was to evaluate the individual and combined effects of a range of multiple agricultural stressors on aquatic insect communities using a series of seven outdoor mesocosm experiments conducted since 2003. The mesocosm studies show that macroinvertebrate community responses can be similar, subtle, or even opposing depending on the stressors investigated and the mechanistic or ecological focus of the study. The current focus on individual chemicals and responses to treatment is misleading. Cumulative effects and multiple sublethal stressors are the norm in impacted ecosystems. A simple, holistic approach to environmental risk assessment is needed

    The effect of yucca on proliferation, apoptosis, and steroidogenesis of porcine ovarian granulosa cells

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    Yucca shidigera is a medicinal plant native to Mexico. Is a plant widely used in folk medicine to treat a variety of ailmentary disorders, but its action on reproductive processes and possible mechanisms of such action remains unknown. Yucca schidigera extract contains a number of steroidal saponins that, because of their biological activity, have attracted attention from the food industry for many years. Yucca extract is used as a natural feed additive with positive effect to microflora, digestion, metabolism and to improve animal muscle growth. Its extract has been used as a foodstuff and folk medicine to treat a wide variety of diseases for many years. Nevertheless, it remaines unknown, whether consumption of yucca can affect reproductive system. The aim of this study was to examine the effects of yucca on basic ovarian cell functions - proliferation, apoptosis and steroidogenesis. Porcine ovarian granulosa cells were cultured with and without yucca extract (added at doses 0; 1; 10 and 100 μg.mL-1 of medium). Markers of proliferation (% of PCNA-positive cells) and apoptosis (% cells containing bax) were analysed by immunocytochemistry. Release of steroid hormones (progesterone and testosterone) was measured by EIA. It was observed, that addition of yucca inhibited proliferation (expression of PCNA), increased apoptosis (expression of bax), stimulated progesterone and inhibited testosterone release. The ability of yucca to reduce ovarian cell proliferation, to promote ovarian cell apoptosis and affect steroidogenesis demonstrates the direct influence of yucca on female gonads. Furthermore, our observations suggest the multiple sites of action (proliferation, apoptosis, steroidogenesis) of yucca on porcine ovarian cell functions. It is not to be excluded, that consumption of yucca can suppress female reproductive functions

    UAS Literary & Arts Journal

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    Proof copy provided by Tidal Echoes.The 2016 edition of Tidal Echoes presents an annual showcase of writers and artists who share one thing in common: a life surrounded by the rainforests and waterways of Southeast Alaska.a heart is a heavy burden -- Editor’s Note -- Acknowledgements -- Always a Pause -- Untitled -- Mishima Teabowls -- Mint Tea and Red Wine -- The Dry Winter Scent of Prairies -- Northern Sunrise -- Musical Theory in a Falling Tree -- Jumbo Lookout -- The Shape of an Echo -- Wonderwall -- It’s Difficult [excerpt from the poem “Marissa”] -- Yéil x’us.eetí Raven Footprints -- táakw winter -- King Fisher -- Bear -- A Dandelion by its own Name -- Migrations -- Untitled -- They Named Her Driftwood -- Kissing in the Rain -- Waltz of the Flowers: Anna and Company -- Sun Catcher -- Porcelain Curtains -- The River -- Kathleen Lake -- A Living Tapestry -- Red Cedar Tlingit Haida Weave -- Skinned -- Survivor -- Auke Lake Lights -- Aurora Chasers -- Emma Afloat -- I Can’t Sleep -- The Ghost I’m Left With -- Framed Memories -- Tequila, Sweat, and Prayers -- The Alchemical Marriage -- A New New Hope -- each dream practice -- Clouds -- Seasons Change and the Waters Run On -- John Muir -- Salmon Speaks -- A Place That Holds Names -- Untitled -- Salmon Spirit Chest, Connected (box) -- The Language of Weaving: Featured Artist Dr. Teri Rofkar -- Nome, Alaska -- Drained -- I’m From -- Srevlla—The state of things where the spring snow is so soft that one sinks into it. -- Reflections -- Txamsem -- Post-Glacial Rebound -- Dressed in Garlands -- Learning the Dance -- Shamrocks -- When You See Me -- Water Spirit -- To Speak for Restraint, for Wildness, for Beauty: Featured Writer Aleria Jensen -- Young Eagle -- Untitled (detail) -- Baula -- Airport Dike Trail Evening -- Ninja Meatballs -- Untitled -- In the Wild Without Child: One Mother’s Invitation to Self -- Whale Tail Vista -- Questions for Anemones -- Yellow Cedarbark Wool on Starfish Pot -- Gleaming Orange and Pissed -- Through the Sky She Comes -- Love for the Honeybee -- The Last Speaker -- Juneau Fireweed -- Judy Plays the Tuba -- Illuminated Juneau -- Airport Dike Trail Moonlight -- Escape -- A Wooden Mother -- Black and Whites -- an excuse for staying indoors (a working title for a work in progress) -- Insecurities -- Lake Farm -- Yew Bear -- Rupture -- Mendenhall Glacier -- The Rookery -- Transient -- Laminaria -- Untitled -- Querencia -- Hoard -- Untitled -- Small Birds Sign -- Selfie at Two -- Entropy -- Goodbye -- Sitka Bridge -- My Remedy -- S1 -- Delta Symbols Static -- Falling -- Breathe Deeply -- Drum, drum away -- Eaglefest Dancer -- Wasichana -- Writer & Artist Biographie

    Promoting Students’ Health at University: Key Stakeholders, Cooperation, and Network Development

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    Background: Cooperation among university units is considered a cornerstone for the promotion of students\u27 health. The underlying mechanisms of health-promoting networks at universities have rarely been examined so far. Shedding light on partnerships is generally limited to the naming of allied actors in a network. Objectives and Methods: In this study, we used network analysis intending to visualize and describe the positions and characteristics of the network actors, and examine organizational relationships to determine the characteristics of the complete network. Results: The network analysis at hand provides in-depth insights into university structures promoting students\u27 health comprising 33 organizational units and hundreds of ties. Both cooperation and communication network show a flat, non-hierarchical structure, which is reflected by its low centralization indices (39–43%) and short average distances (1.43–1.47) with low standard deviations (0.499–0.507), small diameter (3), and the non-existence of subgroups. Density lies between 0.53 and 0.57. According to the respondents, the University Sports Center is considered the most important actor in the context of students\u27 health. Presidium and Institute of Sport and Sports Science play an integral role in terms of network functionality. Conclusion: In the health-promoting network, numerous opportunities for further integration and interaction of actors exist. Indications for transferring results to other universities are discussed. Network analysis enables universities to profoundly analyze their health-promoting structures, which is the basis for sustained network governance and development

    Critical values and variation in type I error along chromosomes in the COGA dataset using the applied pseudo-trait method

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    BACKGROUND: By analyzing a "pseudo-trait," a trait not linked or associated with any of the markers tested, the distribution of the test statistic under the null hypothesis can provide the critical value for the appropriate percentile of the distribution. In addition, the anecdotal observation that p-values tend to be more significant near the telomeres was investigated. RESULTS: The applied pseudo-trait (APT) method was applied to the Affymetrix and Illumina SNPs in the Collaborative Study on the Genetics of Alcoholism dataset to determine appropriate critical values for regression of offspring on mid-parent (ROMP) and Haseman-Elston association and linkage analyses, investigating the occurrence of type I errors in different chromosomal locations, and the extent to which the critical values obtained depend on the type of pseudo-trait used. CONCLUSION: On average, the 5 percentile critical values obtained for this study were less than the expected 0.05. The distribution of p-values does not seem to depend on chromosomal position for ROMP association analysis methods, but does in some cases for Haseman-Elston linkage analysis. Results vary with different pseudo-traits

    Allele frequency misspecification: effect on power and Type I error of model-dependent linkage analysis of quantitative traits under random ascertainment

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    BACKGROUND: Studies of model-based linkage analysis show that trait or marker model misspecification leads to decreasing power or increasing Type I error rate. An increase in Type I error rate is seen when marker related parameters (e.g., allele frequencies) are misspecified and ascertainment is through the trait, but lod-score methods are expected to be robust when ascertainment is random (as is often the case in linkage studies of quantitative traits). In previous studies, the power of lod-score linkage analysis using the "correct" generating model for the trait was found to increase when the marker allele frequencies were misspecified and parental data were missing. An investigation of Type I error rates, conducted in the absence of parental genotype data and with misspecification of marker allele frequencies, showed that an inflation in Type I error rate was the cause of at least part of this apparent increased power. To investigate whether the observed inflation in Type I error rate in model-based LOD score linkage was due to sampling variation, the trait model was estimated from each sample using REGCHUNT, an automated segregation analysis program used to fit models by maximum likelihood using many different sets of initial parameter estimates. RESULTS: The Type I error rates observed using the trait models generated by REGCHUNT were usually closer to the nominal levels than those obtained when assuming the generating trait model. CONCLUSION: This suggests that the observed inflation of Type I error upon misspecification of marker allele frequencies is at least partially due to sampling variation. Thus, with missing parental genotype data, lod-score linkage is not as robust to misspecification of marker allele frequencies as has been commonly thought

    Looking for the bouba-kiki effect in prelexical infants

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    Abstract Adults and toddlers systematically associate certain pseudowords, such as 'bouba' and 'kiki', with round and spiky shapes, respectively. The ontological origin of this so-called bouba-kiki effect is unknown: it could be an unlearned aspect of perception, appear with language exposure, or only emerge with the ability to produce speech sounds (i.e., babbling). We report the results of three experiments with five-and six-month-olds that found no bouba-kiki effect at all. We discuss the consequences of these findings for the emergence of cross-modal associations in infant speech perception

    ANÁLISIS DE PATRONES TERRITORIALES QUE DETERMINAN EL URBANISMO DIVERGENTE: SÍMBOLOS ESPACIALES EN EL DISTRITO ESPECIAL, TURÍSTICO Y CULTURAL DE RIOHACHA

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    Los procesos de urbanización planificada o modelos urbanos bajo órdenes y protocolos, proporciona un patrón de ocupación distinto a los desarrollos espontáneos de  ocupación agrícola o de origen rural. Así se pueden identificar diversos elementos que se producen como resultado de estos esquemas, por ejemplo niveles de contaminación de agua, aire o suelo producto de dichas intervenciones en el territorio que por consiguiente arrojan características que pueden ser típicas. Dichas características o elementos se logran definir como los patrones; puesto que, por determinadas temporadas o lapsos, se presenta un régimen de ocupaciónurbana bien sea sistemática o asimétrica y se manifiesta con características fijas y hasta predecibles en la ocupación del territorio. Así, el cambio en los niveles de contaminación porproductos orgánicos, los aumentos de población asociados a estos incrementos y el consumo energético asociado, siempre refleja una mayor e incremental ocupación del suelo, por lo tanto, estas tres características asociadas conforman un patrón de ocupación del suelo.(Ramos, 2014) en el sentido de lo anterior, el hombre estructura el territorio de acuerdo con las prácticas culturales e interviene los espacios naturales, construyendo una relación antropizada donde se visualizan sobre la superficie del territorio una serie de capas, estratificaciones y redes de servicio que terminan configurando el hábitat humano a partir de la acumulación de espacios físicos que en el tiempo van configurando los patrones culturales, los cuales construyen un entramado simbólico a través de los asentamientos humanos que configuran el territorio y generan variaciones en los patrones paisajísticos (Peña-Cortés, y otros, 2006)
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