3,034 research outputs found

    A Panoply of Cepheid Light Curve Templates

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    We have generated accurate V and I template light curves using a combination of Fourier decomposition and principal component analysis for a large sample of Cepheid light curves. Unlike previous studies, we include short period Cepheids and stars pulsating in the first overtone mode in our analysis. Extensive Monte Carlo simulations show that our templates can be used to precisely measure Cepheid magnitudes and periods, even in cases where there are few observational epochs. These templates are ideal for characterizing serendipitously discovered Cepheids and can be used in conjunction with surveys such as Pan-Starrs and LSST where the observational sampling may not be optimized for Cepheids.Comment: 12 pages, 14 figures. Accepted for publication in AJ fixed embarrassing typo

    Bioactivity of medicinal plants and extracts

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    Nature is an inexhaustible source of bioactive compounds and products with interest- ing medicinal properties and technological applications. Although natural products can be found in plants, animals, microorganisms and minerals, the vast majority of them come from plants ..

    Coupled fracture modes under anti-plane loading

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    The linear elastic analysis of homogeneous, isotropic cracked bodies is a Twentieth Century development. It was recognised that the crack tip stress field is a singularity, but it was not until the introduction of the essentially two dimensional stress intensity factor concept in 1957 that widespread application to practical engineering problems became possible. The existence of three dimensional corner point effects in the vicinity of a corner point where a crack front intersects a free surface was investigated in the late 1970s: it was found that modes II and III cannot exist in isolation. The existence of one of these modes always induces the other. An approximate solution for corner point singularities by BaĹľant and Estenssoro explained some features of corner point effects but there were various paradoxes and inconsistencies. In an attempt to explain these a study was carried out on the coupled in-plane fracture mode induced by a nominal anti-plane (mode III) loading applied to plates and discs weakened by a straight crack. The results derived from a large bulk of finite element models showed clearly that BaĹľant and Estenssoro's analysis is incomplete. Some of the results of the study are summarised, together with some recent results for a disc under in-plane shear loading. On the basis of these results, and a mathematical argument, the results suggest that the stress field in the vicinity of a corner point is the sum of two singularities: one due to stress intensity factors and the other due to an as yet undetermined corner point singularity

    The Place of the Hoplocarida in the Malacostracan Pantheon

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    The stomatopod body plan is highly specialized for predation, yet the Superorder Hoplocarida originated from something other than the lean, mean, killing machine seen today. The fossil record of the group indicates that it originated early on from a non-raptorial ancestor, with the specialized predatory morphology developing much later. The Recent Hoplocarida have been variously positioned within the Malacostraca, from a Subclass equal in rank to the Eumalacostraca (= Caridoida) to being placed as a Superorder within the Eumalacostraca. Consideration of the early fossil morphology, especially of the form of the carapace, of the position and functioning of the articles in the last three pairs of thoracopods, and of other features, suggests that hoplocarids are early derivatives of a basal eumalacostracan stock that was shrimp-like in form. The enhancement of an abdominal respiratory system most likely allowed the development of the anterior thorax into the specialized raptorial system present today

    Attenuation of anxiety-like behavior by helichrysum stoechas (L.) moench methanolic extract through up-regulation of erk signaling pathways in noradrenergic neurons

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    The long-term use of anxiolytic and antidepressant drugs can cause a plethora of side effects and the use of complementary and alternative medicine, which is generally considered safer than conventional medicine, is consistently increasing. Helichrysum stoechas (L.) Moench methanolic extract (HSE) has shown MAO-A inhibitory properties in previous studies. With the aim of obtaining innovative and safer therapies for mood disorders, this study investigated the potential activity of HSE in the management of anxiety-and depression-related symptoms. HSE showed dose-dependent (30–100 mg/kg p.o.) anxiolytic-like activity in the light dark box and marble burying tests, without any antidepressant-like activity, as shown by the results of the tail suspension test. Additionally, HSE did not have any effect on the modulation of pain, which highlights its selectivity in the control of anxiety-related behavior. At active doses, HSE did not produce any sedative effect or result in impaired motor coordination and memory functions. Western blotting experiments showed the ability of HSE to counteract the reduction in the phosphorylation of ERK44/42, to restore brain-derived neurotrophic factor (BDNF) expression and to return cyclic AMP response element binding (CREB) levels to basal levels in noradrenergic hippocampal neurons of mice exposed to an anxiety-related environment, which indicates a protective role against anxiety behavior. These results suggest that oral administration of HSE might represent an interesting opportunity for the management of anxiety disorders

    Lavender (Lavandula angustifolia Mill.) Essential Oil Alleviates Neuropathic Pain in Mice With Spared Nerve Injury

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    Low treatment efficacy represents an important unmet need in neuropathic pain patients and there is an urgent need to develop a more effective pharmacotherapy. An increasing number of patients choose complementary medicine to relieve pain. Lavender essential oil (LEO) is approved by the European Medicines Agency as herbal medicine to relieve anxiety and stress. However, the capability of LEO to relieve other nervous system disorders such as neuropathic pain has never been established. Our work aimed to evaluate the antineuropathic properties of lavender on a spared nerve injury (SNI) model of neuropathic pain in mice. An acute oral administration of LEO (100 mg/kg) alleviated SNI-induced mechanical allodynia, evaluated in the von Frey test, with an intensity comparable to the reference drug pregabalin. Investigations into the mechanism of action showed that LEO markedly decreased the phosphorylation of ERK1, ERK2, and JNK1, and decreased the levels of iNOS in the spinal cord; involvement of the endocannabinoid system was also detected using in vitro inhibition of the FAAH and MALG enzymes as well as in vivo experiments with the CB1 antagonist. Conversely, no effect on P38 phosphorylation and NF-kB activation was detected. These antihyperalgesic effects appeared at the same dose able to induce antidepressant-like, anxiolytic-like, and anorexic effects. In addition, gavage with LEO did not significantly alter animals'' gross behavior, motor coordination, or locomotor activity, nor impaired memory functions. Oral administration of LEO could represent a therapeutic approach in the management of neuropathic pain states

    Modelling and Simulation: An Overview

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    The papers in this special issue of Mathematics and Computers in Simulation cover the following topics: improving judgmental adjustment of model-based forecasts, whether forecast updates are progressive, on a constrained mixture vector autoregressive model, whether all estimators are born equal: the empirical properties of some estimators of long memory, characterising trader manipulation in a limit-order driven market, measuring bias in a term-structure model of commodity prices through the comparison of simultaneous and sequential estimation, modelling tail credit risk using transition matrices, evaluation of the DPC-based inclusive payment system in Japan for cataract operations by a new model, the matching of lead underwriters and issuing firms in the Japanese corporate bond market, stochastic life table forecasting: a time-simultaneous fan chart application, adaptive survey designs for sampling rare and clustered populations, income distribution inequality, globalization, and innovation: a general equilibrium simulation, whether exchange rates affect consumer prices: a comparative analysis for Australia, China and India, the impacts of exchange rates on Australia's domestic and outbound travel markets, clean development mechanism in China: regional distribution and prospects, design and implementation of a Web-based groundwater data management system, the impact of serial correlation on testing for structural change in binary choice model: Monte Carlo evidence, and coercive journal self citations, impact factor, journal influence and article influence

    Online Tea Cafés: Using Caring Science to Transform Digital Learning Spaces and Advance Nursing Leadership

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    Given the current trend toward online nursing education and the recent changes to teaching and learning modalities as a result of a global pandemic, developing a distance-learning pedagogy for students that seeks to explore the power of compassion in the digital world is both timely and necessary. Drawing on pedagogical strategies used in an online nursing course including asynchronous online discussions called Tea Cafés, the authors showcase how they advanced knowledge and understanding in relation to nursing leadership and professional formation. By underpinning the authors’ distance-learning pedagogy in caring science, students not only thrived, but created a strong sense of community, developed leadership skills, and evolved their understanding of how to leverage nursing knowledge via compassion, reflexivity, and politicization to advocate for historically underrepresented communities. By way of student feedback and performance in relation to course learning outcomes, the authors concluded that a pedagogical strategy grounded in caring science can create a reflexive, compassionate, and politicized digital space for transformative learning for both student and educator alike. Compte tenu du mouvement vers la formation virtuelle en sciences infirmières et des changements récents aux modalités d’enseignement et d’apprentissage en lien avec la pandémie mondiale, il est aussi opportun que nécessaire de créer une pédagogie de formation à distance permettant aux étudiantes d’explorer le pouvoir de la compassion dans le monde numérique. En s’inspirant de stratégies pédagogiques employées dans un cours de sciences infirmières en ligne, dont les discussions asynchrones appelées « Cafés-rencontres (Tea Cafés) », les auteures décrivent comment ils font progresser le savoir et la compréhension en lien avec le leadership et la formation professionnelle en sciences infirmières. En ancrant leur pédagogie de la formation à distance sur la science du caring, les étudiantes ont non seulement réussi, mais elles ont aussi créé un fort esprit de communauté, développé des habiletés de leadership et progressé dans leur compréhension des stratégies permettant de mobiliser leurs connaissances pour défendre les communautés historiquement sous-représentées, soit à force de compassion, de réflexion et de sens politique. Selon la rétroaction et la performance des étudiantes au regard des objectifs du cours, les auteurs ont conclu qu’une stratégie pédagogique fondée sur la science du caring peut engendrer un espace numérique réflexif, compatissant et politisé d’apprentissage transformationnel tant pour les étudiantes que les enseignantes

    Opportunities for Public Aquariums to Increase the Sustainability of the Aquatic Animal Trade

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    The global aquatic pet trade encompasses a wide diversity of freshwater and marine organisms. While relying on a continual supply of healthy, vibrant aquatic animals, few sustainability initiatives exist within this sector. Public aquariums overlap this industry by acquiring many of the same species through the same sources. End users are also similar, as many aquarium visitors are home aquarists. Here we posit that this overlap with the pet trade gives aquariums significant opportunity to increase the sustainability of the trade in aquarium fishes and invertebrates. Improving the sustainability ethos and practices of the aquatic pet trade can carry a conservation benefit in terms of less waste, and protection of intact functioning ecosystems, at the same time as maintaining its economic and educational benefits and impacts. The relationship would also move forward the goal of public aquariums to advance aquatic conservation in a broad sense. For example, many public aquariums in North America have been instrumental in working with the seafood industry to enact positive change toward increased sustainability. The actions include being good consumers themselves, providing technical knowledge, and providing educational and outreach opportunities. These same opportunities exist for public aquariums to partner with the ornamental fish trade, which will serve to improve business, create new, more ethical and more dependable sources of aquatic animals for public aquariums, and perhaps most important, possibly transform the home aquarium industry from a threat, into a positive force for aquatic conservation. Zoo Biol. 32:1-12, 2013. © 2012 Wiley Periodicals, Inc

    Reassessing U.S. Coral Reefs

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