3,285 research outputs found

    La "falocedad" de continuos: salud reproductiva entre los adolescentes de Oaxaca de Juárez

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    El presente trabajo explora la salud sexual adolescente en Oaxaca. Basado en un trabajo de campo etnográfico que se ha venido realizando desde el año 2001 sobre las sexualidades adolescentes, examina los sentidos de la iniciación sexual, las creencias tanto populares como biomédicas asociadas con la distinción entre sexualidades masculinas y femeninas, la naturalización de la sexualidad adolescente varonil en general y las implicaciones para la prevención y tratamiento del sida y otras infecciones transmitidas sexualmente. En particular, en este ensayo se comparan, por un lado, los discursos medicalizados relacionados a las nociones de la modernidad y la sexualidad y, por el otro, las ideas tan difundidas de las particularidades culturales de los varones adolescentes en México y en regiones específicas de Oaxaca. Los y las jóvenes en Oaxaca nacen dentro de sistemas ya establecidos de salud reproductiva, cortejo y sexualidades. Estos adolescentes entienden que sus sexualidades están limitadas por factores materiales y culturales e, incluso, por los discursos modernos sobre la sexualidad y las ideas falsas sobre los continuos viriles que establecen que los deseos y comportamientos sexuales son, naturalmente, diferentes entre los varones y las mujeres

    Derivation of the Quantum Probability Rule without the Frequency Operator

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    We present an alternative frequencists' proof of the quantum probability rule which does not make use of the frequency operator, with expectation that this can circumvent the recent criticism against the previous proofs which use it. We also argue that avoiding the frequency operator is not only for technical merits for doing so but is closely related to what quantum mechanics is all about from the viewpoint of many-world interpretation.Comment: 12 page

    Spawning strategies in cypriniform fishes in a lowland river invaded by non-indigenous European barbel Barbus barbus

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    © 2020, The Author(s). Spawning strategies of lowland river fishes include single spawning, where reproduction generally occurs in early spring to provide 0+ fish with an extended growth season through the summer, but with a high risk of stochastic mortality events occurring, such as early summer floods. This risk can be reduced by multiple or protracted spawning strategies, where 0+ fish are produced over an extended period, often into mid-summer, but with the trade-off being a shorter growth season. The spawning strategies of cypriniform fish were explored in the River Teme, a spate river in Western England, which has non-indigenous European barbel Barbus barbus present. Sampling 0+ fish in spring and summer and across three spawning periods, B. barbus, chub Squalius cephalus and minnow Phoxinus phoxinus always revealed multiple spawning events, with 0+ fish of < 20 mm present in samples collected from June to August. Fish below 20 mm in August remained relatively small by the end of their growth season (October). For dace Leuciscus leuciscus, only single spawning events were evident, but with 0+ dace always being relatively large. Therefore, multiple spawning appears to be a common strategy that provides resilience in 0+ fish against stochastic mortality events in lowland rivers

    Whole tumor RNA-sequencing and deconvolution reveal a clinically-prognostic PTEN/PI3K-regulated glioma transcriptional signature

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    The concept that solid tumors are maintained by a productive interplay between neoplastic and non-neoplastic elements has gained traction with the demonstration that stromal fibroblasts and immune system cells dictate cancer development and progression. While less studied, brain tumor (glioma) biology is likewise influenced by non-neoplastic immune system cells (macrophages and microglia) which interact with neoplastic glioma cells to create a unique physiological state (glioma ecosystem) distinct from that found in the normal tissue. To explore this neoplastic ground state, we leveraged several preclinical mouse models of neurofibromatosis type 1 (NF1) optic glioma, a low-grade astrocytoma whose formation and maintenance requires productive interactions between non-neoplastic and neoplastic cells, and employed whole tumor RNA-sequencing and mathematical deconvolution strategies to characterize this low-grade glioma ecosystem as an aggregate of cellular and acellular elements. Using this approach, we demonstrate that optic gliomas generated by altering the germlin

    Predicting the contributions of novel marine prey resources from angling and anadromy to the diet of a freshwater apex predator

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    1. Anadromous fishes can be important prey resources for piscivorous fauna in lowland rivers. Freshwater anglers exploiting large-bodied cypriniform fishes use high quantities of pelletized marine fishmeal baits that can contribute substantially to fish diets. This marine-derived energy pathway also potentially provides a marine prey resource for freshwater piscivores. However, large-bodied cypriniform fishes are often in a size refuge against predation due to their large sizes. 2. Stable isotope (δ15N and δ13C) analysis assessed how novel marine prey resources influenced the diet of a freshwater apex predator, Northern pike Esox lucius, in an impounded river basin (lower River Severn, Western England). Up to three groups of prey resources were present: anadromous European shad (Alosa spp.), cypriniform fishes with dietary specialisms based on marine fishmeal baits, and freshwater prey. The availability of these prey resources to E. lucius varied according to river connectivity and levels of angling exploitation in different river reaches. 3. Where the three prey groups were present, E. lucius were more enriched in δ13C values (range: -24.74 to -16.34 ‰) compared to river reaches where aspects of the marine prey groups were absent. (range: -28.30 to -21.47) In all reaches, δ13C increased as E. lucius length increased. In the reach where all prey groups were present, the isotopic niches of three E. lucius size classes were strongly partitioned; this was not apparent in reaches where the marine pathways were unavailable. 4. Stable isotope mixing models suggested that freshwater prey were the most important prey item, contributing between 42 and 96 % to the diet of individual E. lucius. However, where present, anadromous fishes and cypriniform fishes specialising on marine fishmeal baits were also important prey items, contributing substantially to the diet of larger E. lucius (length > 650 mm). The total dietary contributions of the marine resources varied considerably among the individual larger fish (22 to 58 % of total diet). 5. The presence of two marine resource pathways in a lowland river thus strongly influenced the diet of an apex predator, but with contributions being a function of their spatial availability, E. lucius body size and individual trophic specialisations. These results emphasise how the anthropogenic activities of river engineering and human subsidies can affect the trophic dynamics of apex predators

    Hombres Carnales: Las Políticas Somáticas de la Salud Reproductiva Masculina

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    Este artículo presenta los resultados preliminares de un estudio etnográfico sobre salud reproductiva y sexualidad masculina llevado a cabo en Oaxaca de Juárez, México. Se centra en la decisión de usar métodos anticonceptivos como la vasectomía. Demuestra la forma en que las nociones de salud y sexualidad compartidas por los grupos masculinos de Oaxaca están relacionadas con los discursos médicos y de organizaciones gubernamentales y no-gubernamentales. El autor se remite al concepto de “cultura anti-conceptuva femenina” (Viveros, 2002) para explicar la falta de participación masculina en la planificación familiar. Finalmente, el texto muestra la necesidad de problematizar la medicalización de la sexualidad masculina arguyendo una amplia perspectiva que incluye biología, política e inequidad de poder en las relaciones de género.This article presents the preliminary results of an ethnographic study on reproductive health and masculine sexuality carried out in Oaxaca de Juárez, Mexico. Specifically, it focuses on the decision-making process in the use of anticonceptive procedures such as vasectomy. The author demonstrates how notions of health and sexuality shared by Oaxacan masculine groups are related to the discourses medical commun ity, governmental and non-governmental organizations use to deal with these issues. The author refers to the concept of “anti-conceptive femenine culture” (Viveros, 2002) to explain the lack of men participation in family planning issues. This text shows the need to problematize the medicalization of masculine sexuality arguing a wider perspective that includes biology, politics and power inequality issues embedded in gender relations

    Effective Hamiltonian approach to adiabatic approximation in open systems

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    The adiabatic approximation in open systems is formulated through the effective Hamiltonian approach. By introducing an ancilla, we embed the open system dynamics into a non-Hermitian quantum dynamics of a composite system, the adiabatic evolution of the open system is then defined as the adiabatic dynamics of the composite system. Validity and invalidity conditions for this approximation are established and discussed. A High-order adiabatic approximation for open systems is introduced. As an example, the adiabatic condition for an open spin-12\frac 1 2 particle in time-dependent magnetic fields is analyzed.Comment: 6 pages, 2 figure

    The cell of origin dictates the temporal course of neurofibromatosis-1 (Nf1) low-grade glioma formation.

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    Low-grade gliomas are one of the most common brain tumors in children, where they frequently form within the optic pathway (optic pathway gliomas; OPGs). Since many OPGs occur in the context of the Neurofibromatosis Type 1 (NF1) cancer predisposition syndrome, we have previously employed Nf1 genetically-engineered mouse (GEM) strains to study the pathogenesis of these low-grade glial neoplasms. In the light of the finding that human and mouse low-grade gliomas are composed of Olig2+ cells and that Olig2+ oligodendrocyte precursor cells (OPCs) give rise to murine high-grade gliomas, we sought to determine whether Olig2+ OPCs could be tumor-initiating cells for Nf1 optic glioma. Similar to the GFAP-Cre transgenic strain previously employed to generate Nf1 optic gliomas, Olig2+ cells also give rise to astrocytes in the murine optic nerve in vivo. However, in contrast to the GFAP-Cre strain where somatic Nf1 inactivation in embryonic neural progenitor/stem cells (Nf1flox/mut; GFAP-Cre mice) results in optic gliomas by 3 months of age in vivo, mice with Nf1 gene inactivation in Olig2+ OPCs (Nf1flox/mut; Olig2-Cre mice) do not form optic gliomas until 6 months of age. These distinct patterns of glioma latency do not reflect differences in the timing or brain location of somatic Nf1 loss. Instead, they most likely reflect the cell of origin, as somatic Nf1 loss in CD133+ neural progenitor/stem cells during late embryogenesis results in optic gliomas at 3 months of age. Collectively, these data demonstrate that the cell of origin dictates the time to tumorigenesis in murine optic glioma
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