867 research outputs found
Palatini approach to bouncing cosmologies and DSR-like effects
It is shown that a quadratic gravitational Lagrangian in the Palatini
formulation is able to capture different aspects of quantum gravity
phenomenology in a single framework. In particular, in this theory field
excitations propagating with different energy-densities perceive different
background metrics, a fundamental characteristic of the DSR and Rainbow Gravity
approaches. This theory, however, avoids the so-called soccer ball problem.
Also, the resulting isotropic and anisotropic cosmologies are free from the big
bang singularity. This singularity avoidance occurs non-perturbatively and
shares some similitudes with the effective dynamics of loop quantum cosmology.Comment: 4 pages. Proceedings of Loops'11, Madrid. To appear in Journal of
Physics: Conference Series (JPCS
Hyperspherical Close-Coupling Calculations for Electron-Capture Cross Sections in Low-Energy Ne¹⁰⁺ +H (1s) Collisions
We present total and partial electron-capture cross sections for Ne¹⁰⁺ +H (1s) collisions at energies from 0.01 eV to 1 keV using the hyperspherical close-coupling method. Good agreements with the previous calculations by the classical-trajectory Monte-Carlo method are found for total capture cross section, but not for partial cross sections, especially below about 200 eV/amu. We found that the total cross section is mainly due to the population of n=7 channels and only at energies above 50 eV/amu n = 5,6 channels begin to contribute to the total cross section
Entomology in Ecuador : recent developments and future challenges
We review and analyze the recent development and future challenges facing entomology as a science in Ecuador, a country with limited financial and human resources and numerous environmental problems. Taxonomic studies of the Ecuadorian insect fauna have been well developed for only a few groups (e.g. Papilionoidea, Carabidae) and remains in its infancy for most insect orders. This is due to the huge diversity of species living in a great diversity of habitats and the difficulty to identify most species. There is a lack of published basic biological information and to a high rate of endemism of many groups, especially in the Andes. The development of ecological entomology as a formal discipline in Ecuador is a very recent phenomenon, and has been mostly limited to descriptive studies of the environmental factors that govern insect diversity and abundance. We outline a set of research challenges regarding the impact of global environmental changes on insect communities and habitats they live in and propose potential strategies for the development of entomology in Ecuador. Both basic and applied research will be important in this context as well as international collaboration to strengthen the role of entomological science in decision making processes in the country
Fifty-year study of microplastics ingested by brachyuran and fish larvae in the central English North Sea
\ua9 2023 The Authors. Microplastics (MPs) are ubiquitous pollutants in marine environments. Among the many detrimental consequences of microplastic pollution, its consumption by marine biota is of particular relevance for human health, due to exposure through the food web. Long-term time-series biotic samples are overlooked sources of information for microplastics research. These collections are extremely valuable for the detection and monitoring of changes in marine environments. However, there are very few long-term studies (>10 years) of the uptake of microplastics by biota. Here, we used Dove Time Series planktonic samples (from 1971 to 2020) to assess the presence and prevalence of microplastics in the English North Sea coast over time. Fish and brachyuran larvae were selected due to their commercial importance and consequent implications for human health. A custom enzymatic digestion method was used to extract microplastics for FTIR-ATR polymer identification. An increasing cumulative trend in MP ingestion was identified. Cellophane and polyethylene terephthalate were the polymer types found most frequently in both taxa. Although a total higher microplastics uptake was observed in fish, consumption was not significantly different between taxa over time. Equally, results were not clearly related to microplastics shape or polymer type. This work did not find significant long-term evidence on the increasing uptake of microplastic particles by zooplankton over time. However, the results of this report identified additives, plasticisers, and other more complex and hazardous compounds that should not be released to the environment (e.g., bis-(2-hydroxyethyl) dimerate, propylene glycol ricinoleate) inside marine biota. The study detailed herein provides a case study for the use of long-term time-series in providing accurate assessments of microplastic pollution in marine biota
Psychedelics Promote Structural and Functional Neural Plasticity.
Atrophy of neurons in the prefrontal cortex (PFC) plays a key role in the pathophysiology of depression and related disorders. The ability to promote both structural and functional plasticity in the PFC has been hypothesized to underlie the fast-acting antidepressant properties of the dissociative anesthetic ketamine. Here, we report that, like ketamine, serotonergic psychedelics are capable of robustly increasing neuritogenesis and/or spinogenesis both in vitro and in vivo. These changes in neuronal structure are accompanied by increased synapse number and function, as measured by fluorescence microscopy and electrophysiology. The structural changes induced by psychedelics appear to result from stimulation of the TrkB, mTOR, and 5-HT2A signaling pathways and could possibly explain the clinical effectiveness of these compounds. Our results underscore the therapeutic potential of psychedelics and, importantly, identify several lead scaffolds for medicinal chemistry efforts focused on developing plasticity-promoting compounds as safe, effective, and fast-acting treatments for depression and related disorders
Non-singular Universes a la Palatini
It has recently been shown that f(R) theories formulated in the Palatini
variational formalism are able to avoid the big bang singularity yielding
instead a bouncing solution. The mechanism responsible for this behavior is
similar to that observed in the effective dynamics of loop quantum cosmology
and an f(R) theory exactly reproducing that dynamics has been found. I will
show here that considering more general actions, with quadratic contributions
of the Ricci tensor, results in a much richer phenomenology that yields
bouncing solutions even in anisotropic (Bianchi I) scenarios. Some implications
of these results are discussed.Comment: 4 pages, no figures. Contribution to the Spanish Relativity Meeting
(ERE2010), 6-10 Sept. Granada, Spai
Standardization of Postoperative Care Guidelines for Pediatric Cleft Palate Patients
At a large, community-based pediatric hospital in Southern California, a quality improvement project commenced with a goal to improve patient outcomes by decreasing length of stay and pain levels, while increasing toleration of feeds. Implementing a standardized guideline would ensure safe practice across the continuum and allow providers to use a systematic tool for postoperative care, including nursing care interventions and medications. The Root-Cause-Analysis tool was used to assess the microsystem and determine the contributing factors to the identified problem. A SWOT analysis was then performed, followed by a plan to collect data from all pediatric cleft palate procedures performed at the hospital within the last year. The data collected included all necessary actions that took place upon patient’s exit from surgery. Patient exclusion criteria included PICU admits and those with cleft palate repair resulting from injury. The patients that fell within the exclusion criteria were excluded due to the increased risk and complications that these conditions bear. Considerations for care guideline use include: congenital abnormalities of the heart, brain, or gastrointestinal system as well as those with hematology or oncology conditions and developmental delays. Research was then performed on the patient information found from chart audits, in order to verify the best practices following postoperative cleft palate repair. Ultimately, research on the impact of care guidelines on postoperative cleft palate repair versus physician preference yielded a recommendation for the development of standardized care guidelines, however, the results showed that additional steps are needed to evaluate the results of this implementation on length of stay, pain levels, and time of first tolerated feed
Peculiar outburst of A 0535+26 observed with INTEGRAL, RXTE and Suzaku
A normal outburst of the Be/X-ray binary system A0535+26 has taken place in
August 2009. It is the fourth in a series of normal outbursts that have occured
around the periastron passage of the source, but is unusual by starting at an
earlier orbital phase and by presenting a peculiar double-peaked light curve. A
first "flare" (lasting about 9 days from MJD 55043 on) reached a flux of 440
mCrab. The flux then decreased to less than 220 mCrab, and increased again
reaching 440 mCrab around the periastron at MJD 55057. Target of Opportunity
observations have been performed with INTEGRAL, RXTE and Suzaku. First results
of these observations are presented, with special emphasis on the cyclotron
lines present in the X-ray spectrum of the source, as well as in the pulse
period and energy dependent pulse profiles of the source.Comment: 6 pages, Accepted for publication on PoS, Proceedings of "The Extreme
sky: Sampling the Universe above 10 keV", held in Otranto (Italy) in October
200
Standardization of Postoperative Care Guidelines for Pediatric Cleft Palate Patients
At a large, community-based pediatric hospital in Southern California, a quality improvement project commenced with a goal to improve patient outcomes by decreasing length of stay and pain levels, while increasing toleration of feeds. Implementing a standardized guideline would ensure safe practice across the continuum and allow providers to use a systematic tool for postoperative care, including nursing care interventions and medications. The Root-Cause- Analysis tool was used to assess the microsystem and determine the contributing factors to the identified problem. A SWOT analysis was then performed, followed by a plan to collect data from all pediatric cleft palate procedures performed at the hospital within the last year. The data collected included all necessary actions that took place upon patient’s exit from surgery. Patient exclusion criteria included PICU admits and those with cleft palate repair resulting from injury. The patients that fell within the exclusion criteria were excluded due to the increased risk and complications that these conditions bear. Considerations for care guideline use include: congenital abnormalities of the heart, brain, or gastrointestinal system as well as those with hematology or oncology conditions and developmental delays. Research was then performed on the patient information found from chart audits, in order to verify the best practices following postoperative cleft palate repair. Ultimately, research on the impact of care guidelines on postoperative cleft palate repair versus physician preference yielded a recommendation for the development of standardized care guidelines, however, the results showed that additional steps are needed to evaluate the results of this implementation on length of stay, pain levels, and time of first tolerated feed
La práctica evaluativa de los aprendizajes en el área de Comunicación del nivel secundario desde las percepciones de sus principales actores
La práctica evaluativa es entendida como parte del quehacer cotidiano que realiza el docente en su aula, y que favorece en gran medida el aprendizaje de sus estudiantes. Asimismo, es una actividad sobre la que los docentes requieren tener claridad en ciertos aspectos teóricos que brinden el soporte necesario para su realización.
Esta investigación da respuesta al siguiente problema de investigación ¿Cómo se realiza la práctica evaluativa de los aprendizajes en el área de Comunicación del VII ciclo del nivel secundario desde las percepciones de docentes y estudiantes en una Institución educativa pública de Lima?
La investigación es cualitativa, nivel descriptivo y emplea el método el estudio de casos. Para el recojo de información se aplica dos técnicas. La entrevista a 3 docentes del área de Comunicación y el focus group a 30 estudiantes del VII ciclo del nivel secundario, a fin de conocer las percepciones de estos sobre la práctica evaluativa de los aprendizajes en el área de Comunicación.
Entre los principales hallazgos se destaca el hecho que los docentes y estudiantes manifiestan que la práctica evaluativa tiene un fuerte carácter formativo, porque se procura que los estudiantes estén conscientes de su aprendizaje brindándoles los elementos necesarios para ello. Además, se propicia la participación de los estudiantes en la evaluación, a través de la auto y coevaluación; se destaca el empleo de instrumentos de corte cualitativo como las rúbricas y listas de cotejo, que ayudan a la visualización con mayor claridad de los aspectos a mejorar.Tesi
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