405 research outputs found

    Distinct Contributions of Median Raphe Nucleus to Contextual Fear Conditioning and Fear-Potentiated Startle

    Get PDF
    Ascending 5-HT projections from the median raphe nucleus (MRN), probably to the hippocampus, are implicated in the acquisition of contextual fear (background stimuli), as assessed by freezing behavior. Foreground cues like light, used as a conditioned stimulus (CS) in classical fear conditioning, also cause freezing through thalamic transmission to the amygdala. As the MRN projects to the hippocampus and amygdala, the role of this raphe nucleus in fear conditioning to explicit cues remains to be explained. Here we analyzed the behavior of rats with MRN electrolytic lesions in a contextual conditioning situation and in a fear-potentiated startle procedure. The animals received MRN electrolytic lesions either before or on the day after two consecutive training sessions in which they were submitted to 10 conditioning trials, each in an experimental chamber (same context) where they. received foot-shocks (0.6 mA, 1 sec) paired to a 4-sec light CS. Seven to ten days later, the animals were submitted to testing sessions for assessing conditioned fear when they were placed for five shocks, and the duration of contextual freezing was recorded. The animals were then submitted to a fear-potentiated startle in response to a 4-sec light-CS, followed by white noise (100 dB, 50 ms). Control rats (sham) tested in the same context showed more freezing than did rats with pre- or post-training MRN lesions. Startle was clearly potentiated in the presence of light CS in the sham-lesioned animals. Whereas pretraining lesions reduced both freezing and fear-potentiated startle, the post-training lesions reduced only freezing to context, without changing the fear-potentiated startle. In a second experiment, neurotoxic lesions of the MRN with local injections of N-methyl-D-aspartate or the activation of 5-HT1A somatodendritic auto-receptors of the MRN by microinjections of the 5-HT1A receptor agonist 8-hydroxy- 2-(di-n-propylamino)tetralin (8-OH-DPAT) before the training sessions also reduced the amount of freezing and the fear-potentiated startle. Freezing is a prominent response of contextual fear conditioning, but does not seem to be crucial for the enhancement of the startle reflex by explicit aversive cues. As fear-potentiated startle may be produced in posttraining lesioned rats that are unable to freeze to fear contextual stimuli, dissociable systems seem to be recruited in each condition. Thus, contextual fear and fear-potentiated startle are conveyed by distinct 5-HT-mediated circuits of the MRN

    Risk Theory with Affine Dividend Payment Strategies

    Get PDF
    We consider a classical compound Poisson risk model with affine dividend payments. We illustrate how both by analytical and probabilistic techniques closed-form expressions for the expected discounted dividends until ruin and the Laplace transform of the time to ruin can be derived for exponentially distributed claim amounts. Moreover, numerical examples are given which compare the performance of the proposed strategy to classical barrier strategies and illustrate that such affine strategies can be a noteworthy compromise between profitability and safety in collective risk theory

    Nutrição e produção de máteria seca de milho submetido a calagem e adubação sulfatada.

    Get PDF
    A calagem é uma prática indispensável para obtenção de altos rendimentos das culturas, em solos tropicais ácidos. Objetivou-se avaliar a nutrição e produção de matéria seca de milho, em solo submetido a calagem estimada por três métodos de cálculo e adubação sulfatada. O experimento foi desenvolvido em casa-de-vegetação, em tubos de PVC, com uma planta por tubo. Utilizou-se Latossolo Vermelho distrófico (LVd), sob vegetação nativa. Foi aplicado calcário dolomítico, tipo filler, nas doses de 4,2 Mg ha-1; 6,7 Mg ha-1; e 8,0 Mg ha-1, calculadas pelo método do alumínio trocável, cálcio e magnésio; método da elevação da saturação por bases; e método do tampão SMP, respectivamente, além do tratamento sem aplicação de calcário, combinados com três doses de S (10 mg dm-3, 30 mg dm-3 e 60 mg dm-3), mais o tratamento sem adição de enxofre. As plantas de milho foram colhidas aos 45 dias após a semeadura, sendo separada a parte aérea do sistema radicular. O método mais eficiente de recomendação de calagem para o milho foi o método da elevação da saturação por bases. A aplicação de doses de enxofre não teve efeito no desenvolvimento do milho, até o estádio avaliado

    Existence and Optimality of ww-Non-adjacent Forms with an Algebraic Integer Base

    Full text link
    We consider digital expansions in lattices with endomorphisms acting as base. We focus on the ww-non-adjacent form (ww-NAF), where each block of ww consecutive digits contains at most one non-zero digit. We prove that for sufficiently large ww and an expanding endomorphism, there is a suitable digit set such that each lattice element has an expansion as a ww-NAF. If the eigenvalues of the endomorphism are large enough and ww is sufficiently large, then the ww-NAF is shown to minimise the weight among all possible expansions of the same lattice element using the same digit system

    Water and Us: tales and hands-on laboratories to educate about sustainable and nonconflictual water resources management

    Get PDF
    Climate change and water security are among the grand challenges of the 21st century, but literacy on these matters among high-school students is often unsystematic and/or detached from the real world. This study aims to introduce the educational objectives, methods, and early results of “Water and Us”, a three-module initiative that can contribute to advancing water education in a warming climate by focusing on the natural and anthropogenic water cycle, climate change, and emerging water conflicts. The method of Water and Us revolves around storytelling to aid understanding and generate new knowledge, learning by doing, a flipped-classroom environment, and a constant link to examples from the real world (such as ongoing droughts across the world or seeds of conflict regarding transnational river basins). Water and Us was established in 2021–2022 and, during that school year, involved ≥200 students as part of a proof of concept to test the complete didactic approach using small-scale experiments. Results from ≥40 h of proof-of-concept events confirmed the effectiveness of this approach with respect to conveying the essential elements of the natural and anthropogenic water cycle, the most commonly recurring concepts related to climate change and water as well as the possible conflicts and solutions related to water scarcity in a warming climate. The Water and Us team remains interested in networking with colleagues and potential recipients to upscale and further develop this work.</p

    Specialized active leprosy search strategies in an endemic area of the Brazilian Amazon identifies a hypermutated Mycobacterium leprae strain causing primary drug resistance

    Get PDF
    INTRODUCTION: Leprosy, an infectious disease caused by Mycobacterium leprae, remains a public health concern in endemic countries, particularly in Brazil. In this study, we conducted an active surveillance campaign in the hyperendemic city of Castanhal in the northeastern part of the state of Pará using clinical signs and symptoms combined with serological and molecular tools to diagnose new cases and to identify drug resistance of circulating M. leprae strains and their distribution in the community. METHODS: During an active surveillance of one week, we enrolled 318 individuals using three different strategies to enroll subjects for this study: (i) an active survey of previously treated cases from 2006 to 2016 found in the Brazil National Notifiable Disease Information System database (n = 23) and their healthy household contacts (HHC) (n = 57); (ii) an active survey of school children (SC) from two primary public schools in low-income neighborhoods (n = 178), followed by visits to the houses of these newly diagnosed SC (n = 7) to examine their HHC (n = 34) where we diagnosed additional new cases (n = 6); (iii) and those people who spontaneously presented themselves to our team or the local health center with clinical signs and/or symptoms of leprosy (n = 6) with subsequent follow-up of their HHC when the case was confirmed (n = 20) where we diagnosed two additional cases (n = 2). Individuals received a dermato-neurological examination, 5 ml of peripheral blood was collected to assess the anti-PGL-I titer by ELISA and intradermal earlobe skin scrapings were taken from HHC and cases for amplification of the M. leprae RLEP region by qPCR. RESULTS: Anti-PGL-I positivity was highest in the new leprosy case group (52%) followed by the treated group (40.9%), HHC (40%) and lowest in SC (24.6%). RLEP qPCR from SSS was performed on 124 individuals, 22 in treated cases, 24 in newly diagnosed leprosy cases, and 78 in HHC. We detected 29.0% (36/124) positivity overall in this sample set. The positivity in treated cases was 31.8% (7/22), while in newly diagnosed leprosy cases the number of positives were higher, 45.8% (11/23) and lower in HHC at 23.7% (18/76). Whole genome sequencing of M. leprae from biopsies of three infected individuals from one extended family revealed a hypermutated M. leprae strain in an unusual case of primary drug resistance while the other two strains were drug sensitive. DISCUSSION: This study represents the extent of leprosy in an active surveillance campaign during a single week in the city of Castanhal, a city that we have previously surveyed several times during the past ten years. Our results indicate the continuing high transmission of leprosy that includes fairly high rates of new cases detected in children indicating recent spread by multiple foci of infection in the community. An unusual case of a hypermutated M. leprae strain in a case of primary drug resistance was discovered. It also revealed a high hidden prevalence of overt disease and subclinical infection that remains a challenge for correct clinical diagnosis by signs and symptoms that may be aided using adjunct laboratory tests, such as RLEP qPCR and anti-PGL-I serology

    ANALISIS YURIDIS SOSIOLOGIS PROSEDUR PENYELAMATAN KREDIT BERMASALAH BANK DANAMON BERDASARKAN PERATURAN BANK INDONESIA NOMOR 14/15/PBI/2012 TENTANG PENILAIAN KUALITAS ASET BANK UMUM (Studi Pada Kasus Konflik Bank Danamon Tanjung Balai Karimun Provinsi Kepualauan Riau Dengan Nasabah Bank Danamon)

    Get PDF
    Kasus mengenai penanganan kredit bermasalah di Bank Danamon sering mengalami permasalahan terutama dalam hal pelelangan. Kejadian tersebut dikarenakan bahwa Bank Danamon sering melakukan tindakan pelelangan tanpa pemberitahuan oleh nasabah serta tidak melakukan proses penyelamatan kredit bermasalah terlebih dahulu terhadap nasabah yang mengalami kredit bermasalah. Penelitian ini mengambil rumusan masalah Bagaimana prosedur penyelamatan kredit bermasalah yang dilakukan oleh PT.Bank Danamon dikaitkan dengan Peraturan Bank Indonesia Nomor 14/15/PBI/2012 Tentang Penilaian Kualitas Aset Bank Umum dan Apa faktor yang mendasari PT.Bank Danamon melakukan pelelangan terhadap jaminan nasabah. Penelitian ini menggunakan pendekatan Yuridis Sosiologis. Berdasarkan hasil penelitian tersebut ada beberapa peraturan dari Bank Danamon yang tidak mengikuti prosedur dari BI serta terjadi ketidaksesuain dengan peraturan yang dikeluarkan oleh Bank Danamon pusat dengan tindakan yang dilakukan oleh Bank Danamon Tanjung Balai Karimun. Proses penyelamatan kredit bermasalah yang dilakukan oleh bank adalah dengan mengeluarkan surat penggilan yang berisi mengenai pelunasan pembayaran, Bank Danamon tidak melakukan restrukturisasi sebelum nasabah sendiri yang membuat permohonan untuk dapat restrukturisasi. Mengenai pelelangan Bank Danmon kurang melengkapi salah satu persyaratan untuk melakukan lelng yaitu tidak adanya surat pemberitahuan lelang kepada debitur sehingga pelelangan yang dilakukan oleh bank danamon kurang sempurna. Kesimpulannya bahwa Bank Danamon Tanjung Balai Karimun kurang menerapkan peraturan yang telah dikeluarkan oleh Bank Danamon Pusat. Saran, Bank Danamon Tanjung Balai Karimun dapat memperbaiki kinerja bank dan melakukan perbuatan sesuai dengan perturan yang telah dikeluarkan

    Perceptions of the targets and sources of COVID-19 threat are structured by group memberships and responses are influenced by identification with humankind

    Get PDF
    This research was supported by a grant from the German Research Foundation awarded to RvD, NMJ, and JAH (DI 848/15-1 and HA 6455/4-1). Data collection for this study was supported by a grant from the association of friends and supporters (Freunde & Förderer) at Goethe University.The purpose of this study was to investigate which social groups are perceived as a threat target and which are perceived as a threat source during the COVID-19 outbreak. In a German sample (N = 1454) we examined perceptions of social groups ranging from those that are psychologically close and smaller (family, friends, neighbors) to those that are more distal and larger (people living in Germany, humankind). We hypothesized that psychologically closer groups would be perceived as less affected by COVID-19 as well as less threatening than more psychologically distal groups. Based on social identity theorizing, we also hypothesized that stronger identification with humankind would change these patterns. Furthermore, we explored how these threat perceptions relate to adherence to COVID-19 health guidelines. In line with our hypotheses, latent random-slope modelling revealed that psychologically distal and larger groups were perceived as more affected by COVID-19 and as more threatening than psychologically closer and smaller groups. Including identification with humankind as a predictor into the threat target model resulted in a steeper increase in threat target perception patterns, whereas identification with humankind did not predict differences in threat source perceptions. Additionally, an increase in threat source perceptions across social groups was associated with more adherence to health guidelines, whereas an increase in threat target perceptions was not. We fully replicated these findings in a subgroup from the original sample (N = 989) four weeks later. We argue that societal recovery from this and other crises will be supported by an inclusive approach informed by a sense of our common identity as human beings.Publisher PDFPeer reviewe

    A trouble shared is a trouble halved : the role of family identification and identification with humankind in well-being during the COVID-19 pandemic

    Get PDF
    This research was supported by a grant from the German Research Foundation awarded to RvD, NMJ, and JAH (DI 848/15-1 and HA 6455/4-1). The data collection for this study was supported by a grant from the association of friends and supporters (Freunde & Förderer) at Goethe University.The COVID-19 pandemic has triggered health-related anxiety in ways that undermine peoples’ mental and physical health. Contextual factors such as living in a high-risk area might further increase the risk of health deterioration. Based on the Social Identity Approach, we argue that social identities can not only be local that are characterized by social interactions, but also be global that are characterized by a symbolic sense of togetherness and that both of these can be a basis for health. In line with these ideas, we tested how identification with one’s family and with humankind relates to stress and physical symptoms while experiencing health-related anxiety and being exposed to contextual risk factors. We tested our assumptions in a representative sample (N = 974) two-wave survey study with a 4-week time lag. The results show that anxiety at Time 1 was positively related to stress and physical symptoms at Time 2. Feeling exposed to risk factors related to lower physical health, but was unrelated to stress. Family identification and identification with humankind were both negatively associated with subsequent stress and family identification was negatively associated with subsequent physical symptoms. These findings suggest that for social identities to be beneficial for mental health, they can be embodied as well as symbolic.Publisher PDFPeer reviewe
    corecore