495 research outputs found

    Temporal stability, cross-validity, and external validity of risk preferences measures: experimental evidence from a UK representative sample

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    We conduct an “artefactual” field experiment to incorporate three different risk preferences measures within the Innovation Panel (IP) of the UK Household Longitudinal Survey (UKHLS). We randomly allocate to an experimental module a nationally representative sample of 661 adult respondents to the IP Wave 6 (IP6). These subjects respond to the incentive-compatible tasks by Holt and Laury (2002) (HL), and by Binswanger (1980, 1981) and Eckel and Grossman (2008) (B-EG), and to the SOEP survey questions by Dohmen et al. (2011) for self-reported willingness to take risks in general (SOEP-G), in finance (SOEP-F), and in health (SOEP-H). One year later (IP7) the same measures are repeated for 413 of these respondents. This design allows us to systematically test, for a UK representative sample, the validity of the three measures along three dimensions. First, we look at cross-validity by testing how responses at one point in time correlate across the three tasks, assuming a Constant Relative Risk Aversion (CRRA) utility function. Second, we look at temporal stability by comparing the responses across IP6 and IP7. Third, we look at external validity by considering a range of risky health and financial behaviors in the UKHLS. We have three main findings. First, concerning cross-validity, we find evidence that the different measures generally correlate and map into each other, although their associations are not perfect. Second, concerning temporal stability, there are significant and positive correlations of the B-EG, HL, and SOEP measures across IP6 and IP7. Finally, we find mixed evidence concerning external validity

    I call BS: Fraud Detection in Crowdfunding Campaigns

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    Donations to charity-based crowdfunding environments have been on the rise in the last few years. Unsurprisingly, deception and fraud in such platforms have also increased, but have not been thoroughly studied to understand what characteristics can expose such behavior and allow its automatic detection and blocking. Indeed, crowdfunding platforms are the only ones typically performing oversight for the campaigns launched in each service. However, they are not properly incentivized to combat fraud among users and the campaigns they launch: on the one hand, a platform's revenue is directly proportional to the number of transactions performed (since the platform charges a fixed amount per donation); on the other hand, if a platform is transparent with respect to how much fraud it has, it may discourage potential donors from participating. In this paper, we take the first step in studying fraud in crowdfunding campaigns. We analyze data collected from different crowdfunding platforms, and annotate 700 campaigns as fraud or not. We compute various textual and image-based features and study their distributions and how they associate with campaign fraud. Using these attributes, we build machine learning classifiers, and show that it is possible to automatically classify such fraudulent behavior with up to 90.14% accuracy and 96.01% AUC, only using features available from the campaign's description at the moment of publication (i.e., with no user or money activity), making our method applicable for real-time operation on a user browser

    Intellectual functioning in pediatric patients with epilepsy: a comparison of medically controlled, medically uncontrolled and surgically controlled children

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    OBJETIVO: Comparar o quociente intelectual (QI) em três grupos de crianças com epilepsia: 1) controlados com medicação, 2) não controlados com medicação e 3) controlados com cirurgia. MÉTODOS: Noventa e oito pacientes pediátricos, com idades entre 6 e 12 anos, foram selecionados de dezembro de 2007 a julho de 2008. A Escala de Inteligência Wechsler para Crianças - terceira edição (WISC-III) foi utilizada para a avaliação neuropsicológica dos pacientes. Os resultados foram relacionados com a síndrome epiléptica, a etiologia da epilepsia, o tratamento medicamentoso, a idade do paciente no início da epilepsia e a duração da epilepsia. RESULTADOS: Os escores da WISC foram significativamente melhores no grupo controlado com medicação quando comparados aos do grupo não controlado com medicação. O grupo controlado com medicação obteve um desempenho significativamente melhor na maioria dos subtestes da WISC quando comparado ao grupo não controlado com medicação: vocabulário, aritmética, compreensão, memória de dígitos, completar figuras, arranjo de figuras e cubos. Um número significativamente maior de pacientes com epilepsia idiopática e uso de monoterapia foi observado no grupo controlado com medicação quando comparado ao grupo não controlado. O grupo controlado com cirurgia não apresentou diferença significativa no desempenho do QI quando comparado ao grupo controlado com medicação. CONCLUSÕES: As crianças com um bom controle de crises tiveram um melhor desempenho no QI geral, verbal e de execução quando comparadas às crianças com epilepsia refratária. Esses resultados podem ser influenciados por fatores clínicos como o uso de monoterapia, o tipo de droga antiepiléptica utilizada, a síndrome epiléptica e a etiologia da epilepsia. A cirurgia de epilepsia pode causar um impacto positivo no desempenho cognitivo das crianças que ficaram livres de crises após o procedimento cirúrgico.OBJECTIVE: To compare the intellectual coefficient (IQ) of three groups of children with epilepsy: 1) medically controlled, 2) medically uncontrolled and 3) surgically controlled. METHODS: From December 2007 until July 2008, 98 pediatric patients were selected, with an age range between 6 and 12 years. Neuropsychological assessment included the Wechsler Intelligence Scale for Children - third edition (WISC-III). Results are related to epileptic syndrome, etiology of epilepsy, drug therapy, age at epilepsy onset and epilepsy duration. RESULTS: WISC scores were significantly better in the medically controlled group when compared to the medically uncontrolled group. The medically controlled group performed significantly better in the majority of the WISC subtests when compared to the medically uncontrolled group: vocabulary, arithmetic, comprehension, digit span, picture completion, picture arrangement, and block design. A significantly higher number of idiopathic epilepsy and monotherapy cases was observed in the medically controlled group when compared to the medically uncontrolled group. Surgically controlled children had no significant differences in IQ performance when compared to medically controlled children. CONCLUSIONS: Children with good seizure control have higher general, verbal and performed intelligence when compared to children with refractory epilepsy. These results may be influenced by clinical factors such as use of monotherapy, drug type and epileptic syndrome and etiology. Epilepsy surgery can have a positive impact on cognitive performance of children who were free of seizures after surgery

    Entomopathogenic potential of bacteria associated with soil-borne nematodes and insect immune responses to their infection

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    Soil-borne nematodes establish close associations with several bacterial species. Whether they confer benefits to their hosts has been investigated in only a few nematode-bacteria systems. Their ecological function, therefore, remains poorly understood. In this study, we isolated several bacterial species from rhabditid nematodes, molecularly identified them, evaluated their entomopathogenic potential on Galleria mellonella larvae, and measured immune responses of G. mellonella larvae to their infection. Bacteria were isolated from Acrobeloides sp., A. bodenheimeri, Heterorhabditis bacteriophora, Oscheius tipulae, and Pristionchus maupasi nematodes. They were identified as Acinetobacter sp., Alcaligenes sp., Bacillus cereus, Enterobacter sp., Kaistia sp., Lysinibacillus fusiformis, Morganella morganii subsp. morganii, Klebsiella quasipneumoniae subsp. quasipneumoniae, and Pseudomonas aeruginosa. All bacterial strains were found to be highly entomopathogenic as they killed at least 53.33% G. mellonella larvae within 72h post-infection, at a dose of 106 CFU/larvae. Among them, Lysinibacillus fusiformis, Enterobacter sp., Acinetobacter sp., and K. quasipneumoniae subsp. quasipneumoniae were the most entomopathogenic bacteria. Insects strongly responded to bacterial infection. However, their responses were apparently little effective to counteract bacterial infection. Our study, therefore, shows that bacteria associated with soil-borne nematodes have entomopathogenic capacities. From an applied perspective, our study motivates more research to determine the potential of these bacterial strains as biocontrol agents in environmentally friendly and sustainable agriculture

    Determination of tranexamic acid in human plasma by UHPLC coupled with tandem mass spectrometry targeting sub-microgram per milliliter levels

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    Tranexamic acid (TXA) is an antifibrinolytic drug, with the ability to inhibit lysine binding at plasminogen receptors, used in adult trauma patients with on-going or at risk of significant haemorrhage. To understand the pharmacokinetics and pharmacodynamics of this drug in variable age groups undergoing surgeries with high blood loss, effective methods for determination of TXA in biological samples at sub-μg mL−1 are still required. We describe herein the development and validation of a method based on ultra-high performance liquid chromatography coupled to triple quadrupole-tandem mass spectrometry to quantify TXA in human plasma. An inexpensive, simple and efficient sample clean-up was implemented, not requiring matrix-matching calibration. Sample preparation consisted in protein precipitation using acetonitrile containing 0.5% (v/v) formic acid, followed by hydrophilic interaction based chromatographic separation, with elution in isocratic mode using a combination of acetonitrile and water (75:25, v/v), with quantification of TXA based on selected reaction monitoring. Good linearity was achieved (r2 > 0.997) for TXA concentrations ranging from 30 to 600 ng mL−1, with LOD of 18 ng mL−1 in plasma. The developed method proved to be selective, sensitive, accurate (96.4–105.7% of nominal values) and precise (RSD ≤ 4.5%). TXA was found to be stable in plasma extracts standing 24 h at room temperature (20 °C) or in the autosampler, and after three freeze-thawing cycles. Mean recovery values of TXA spiked plasma samples were ≥91.9%. No significant matrix effects were observed. The proposed methodology was successfully applied to the clinical study of plasma samples recovered during scoliosis surgery of pediatric patients pretreatment with TXA.info:eu-repo/semantics/publishedVersio

    Avaliação da germinação de sementes de açaízeiro (Euterpe oleracea M.) Submetidas à inoculação de 19 linhagens de bactérias isoladas no semiárido / Evaluation of seeds germination of açaízeiro (Euterpe oleracea M.) Submitted to the inoculation of 19 lines of semi-arid isolated bacteria.

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    O açaizeiro é uma fruteira nativa da Amazônia que vem conquistando o mercado nacional e internacional mediante comercialização da bebida in natura (suco), bem como da congelada. Essa bebida é obtida pelo processamento da parte comestível dos seus frutos, que são denominados açaí. A aplicação de reguladores de crescimento via semente tem sido proposta por várias empresas. Esses reguladores são definidos como substâncias naturais ou sintéticas que podem ser aplicadas diretamente nas plantas, em sementes e no solo, com a finalidade de incrementar a produção e melhorar a germinação das sementes. As classes de reguladores vegetais reconhecidas são as auxinas, giberelinas, citocininas, retardadores e inibidores, e o etileno. As auxinas também são produzidas durante o processo de germinação e estão envolvidas na permeabilidade das membranas e possuem relação direta com o crescimento de plântulas. Objetivou-se avaliar a germinação das sementes de açaízeiro inoculadas com 19 linhagens de bactérias coletadas na região do Semiárido potiguar capazes de fixar nitrogênio, solubilização de fosfato e produzir auxinas. O experimento foi conduzido no Laboratório de Nanobiotecnolgia e Biorreatores – LABIN e no Laboratório de Análises de Sementes ambos pertencentes a Universidade Federal Rural do Semi-Árido. Foram inoculadas três sementes de açaí para cada grupo de bactéria, sendo que em uma amostra foi administrada sem a inoculação a fim de verificar a evolução. O teste de germinação foi conduzido em papel toalha (Germitest®) que foi acondicionado em sacos plásticos transparente e colocados em câmaras de germinação do tipo Biochemical Oxigen Demand (B.O.D.), com fotoperíodo artificial adequado. Dez 10 dias após a semeadura, verificou-se que grande parte das sementes inoculadas com bactéria germinaram. As que foram inoculadas com as de número BAC 5, BAC 13 e BAC 15 tiveram crescimento acelerado (mais vigorosas) apresentando nodulação nas raízes e liberando exudado de cor roseado. Equanto que as inoculadas com os números 0, BAC 1, BAC 2, BAC 3, BAC 4, BAC 6, BAC 9, BAC 12 e BAC 14 resultaram em germinação lenta e menos vigorosas. Já as de números BAC 7, BAC 8, BAC 10, BAC 11, BAC 17, BAC 18, BAC 20 e BAC 27 obtiveram crescimento moderado. Com relação ao período previsto para a germinação, as sementes que foram inoculadas com as bactérias germinaram em tempo muito inferior ao previsto em média (90 dias)

    On the bioactivity of Echinacea purpurea extracts to modulate the production of inflammatory mediators

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    Inflammatory diseases are the focus of several clinical studies, due to limitations and serious side effects of available therapies. Plant-based drugs (e.g., salicylic acid, morphine) have become landmarks in the pharmaceutical field. Therefore, we investigated the immunomodulatory effects of flowers, leaves, and roots from Echinacea purpurea. Ethanolic (EE) and dichloromethanolic extracts (DE) were obtained using the Accelerated Solvent Extractor and aqueous extracts (AE) were prepared under stirring. Their chemical fingerprint was evaluated by liquid chromatography–high resolution mass spectrometry (LC-HRMS). The pro- and anti-inflammatory effects, as well as the reduction in intracellular reactive oxygen and nitrogen species (ROS/RNS), of the different extracts were evaluated using non-stimulated and lipopolysaccharide-stimulated macrophages. Interestingly, AE were able to stimulate macrophages to produce pro-inflammatory cytokines (tumor necrosis factor -TNF-α, interleukin -IL-1β, and IL-6), and to generate ROS/RNS. Conversely, under an inflammatory scenario, all extracts reduced the amount of pro-inflammatory mediators. DE, alkylamides-enriched extracts, showed the strongest anti-inflammatory activity. Moreover, E. purpurea extracts demonstrated generally a more robust anti-inflammatory activity than clinically used anti-inflammatory drugs (dexamethasone, diclofenac, salicylic acid, and celecoxib). Therefore, E. purpurea extracts may be used to develop new effective therapeutic formulations for disorders in which the immune system is either overactive or impaired.This research was funded by the Fundação para a Ciência e a Tecnologia (FCT) to the PhD grant of SFV (PD/BD/135246/2017 and COVID/BD/152012/2021) and the projects PATH (PD/00169/2013), FROnTHERA (NORTE-01-0145-FEDER-000023), Cells4_IDs (PTDC/BTM-SAL/28882/2017), and the NORTE 2020 Structured Project, co-funded by Norte2020 (NORTE-01-0145-FEDER-000021). This research was also partially supported by national funds by FCT through the projects UIDB/04423/2020 and UIDP/04423/2020 (Group of Natural Products and Medicinal Chemistry-CIIMAR) and ERDF, through the COMPETE—POFC program in the framework of the program PT2020

    A COLLABORATIVE VIRTUAL ENVIRONMENT FOR TRAINING OF SECURITY AGENTS IN NUCLEAR EMERGENCIES

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    In face the recently observed security menaces related to terrorist actions and natural disasters, there is a need for a major qualification and training of the agents responsible for avoid any problems regarding to abnormal conditions. In the conventional training procedures, however, field simulations are associated to logistical and operational constraints regarded to the execution of the tests which can expose the user to risk. On the other hand, the use of virtual simulations provides an alternative to such limitations besides of promote the qualifying of professionals with a great reliability. For this reason, this paper proposes the development of a collaborative virtual environment that will be used to prepare the security agents on identifying individuals suspected of carrying radioactive materials. The development of the virtual environment consisted on modeling using Autodesk 3ds Max, where the scene itself and the scene objects were modeled besides the terrain creation and basic features programming using the Game Engine Unity 3D. In the Engine Game were included radiation detectors and avatars. The security agents were able to communicate to each other by means of auxiliary external tools like a headset software that makes possible the communication, coordination and cooperation required for an effective collaboration. Experimental tests of the virtual simulations were performed with the participation of CNEN radiological protection agents and collaborators. The tests have shown that the proposed method can contribute to improve the training results of the basic collaborative skills required for a CNEN agent in an emergency situation without the need to espose him to any kind of risk. In face of that, we hope that it can contribute to minimize the demand for qualified security professionals
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