47 research outputs found

    Termite mound architecture regulates nest temperature and correlates with species identities of symbiotic fungi.

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    Background Large and complex mounds built by termites of the genus Macrotermes characterize many dry African landscapes, including the savannas, bushlands, and dry forests of the Tsavo Ecosystem in southern Kenya. The termites live in obligate symbiosis with filamentous fungi of the genus Termitomyces. The insects collect dead plant material from their environment and deposit it into their nests where indigestible cell wall compounds are effectively decomposed by the fungus. Above-ground mounds are built to enhance nest ventilation and to maintain nest interior microclimates favorable for fungal growth. Objectives In Tsavo Ecosystem two Macrotermes species associate with three different Termitomyces symbionts, always with a monoculture of one fungal species within each termite nest. As mound architecture differs considerably both between and within termite species we explored potential relationships between nest thermoregulatory strategies and species identity of fungal symbionts. Methods External dimensions were measured from 164 Macrotermes mounds and the cultivated Termitomyces species were identified by sequencing internal transcribed spacer (ITS) region of ribosomal DNA. We also recorded the annual temperature regimes of several termite mounds to determine relations between mound architecture and nest temperatures during different seasons. Results Mound architecture had a major effect on nest temperatures. Relatively cool temperatures were always recorded from large mounds with open ventilation systems, while the internal temperatures of mounds with closed ventilation systems and small mounds with open ventilation systems were consistently higher. The distribution of the three fungal symbionts in different mounds was not random, with one fungal species confined to “hot nests.” Conclusions Our results indicate that different Termitomyces species have different temperature requirements, and that one of the cultivated species is relatively intolerant of low temperatures. The dominant Macrotermes species in our study area can clearly modify its mound architecture to meet the thermal requirements of several different symbionts. However, a treacherous balance seems to exist between symbiont identity and mound architecture, as the maintenance of the thermophilic fungal species obviously requires reduced mound architecture that, in turn, leads to inadequate gas exchange. Hence, our study concludes that while the limited ventilation capacity of small mounds sets strict limits to insect colony growth, in this case, improving nest ventilation would invariable lead to excessively low nest temperatures, with negative consequences to the symbiotic fungus.Peer reviewe

    Katsaus yhteiskunnalliseen yrittäjyyteen matkailussa: osallisuuden mahdollisuudet pohjoisen urbaaneissa paikallisyhteisöissä

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    The purpose of this literature review is to explore how social entrepreneurship research is conducted in the field of tourism and to consider the possibilities, limitations and challenges, which are included in it in urban, northern environment. Social entrepreneurship in tourism can be attached to a larger context of the inclusion and possibilities of inclusion, which are in tourism research discussed in terms of social and inclusive tourism. The impact of social entrepreneurship is namely on the social: communities and societies. It aims in producing meaningful influence besides economic benefit to the society. In this review, we first explore how social entrepreneurship is discussed in the field of tourism research. We also reflect what kind of viewpoints the discussions offer to social entrepreneurship in tourism in the northern, urban context. Based on the review, the central terms of social entrepreneurship in tourism are value creation, social innovations and sustainability. The aim of the social enterprises in tourism is especially to develop the living conditions of the community through, for instance, creating jobs, increasing the employability of those at risk of exclusion and supporting communities in the periphery. The social enterprises are studied very little in the context of urban north since the studies focus on rural destinations

    Differential Effects of Virtual and Concrete Manipulatives in a Fraction Intervention on Fourth and Fifth Grade Students’ Fraction Skills

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    Fraction knowledge has been found to predict later mathematical performance, but many students have difficulty with fractions. Virtual manipulatives (VM) and concrete manipulatives (CM) are effective approaches to teaching fractions, but previous research has not been able to reach a consensus on which manipulatives are the most effective. This quasi-experimental study employed a pre- and posttest design to investigate the differential effects of VM and CM in a fraction intervention on students’ fraction skills. In addition to fraction skills, students’ arithmetic fluency was measured. Fidelity of intervention, social validity, and time-efficiency of the manipulatives were also investigated. Fourth- and fifth-grade participants (N= 115) from Southern Finland were assigned to VM and CM intervention groups. The intervention was implemented during six 45-minute lessons over 2 weeks. Results revealed that the CM group outperformed the VM group in fraction skills, which suggests that CM should be favored in fraction interventions.Fraction knowledge has been found to predict later mathematical performance, but many students have difficulty with fractions. Virtual manipulatives (VM) and concrete manipulatives (CM) are effective approaches to teaching fractions, but previous research has not been able to reach a consensus on which manipulatives are the most effective. This quasi-experimental study employed a pre- and posttest design to investigate the differential effects of VM and CM in a fraction intervention on students’ fraction skills. In addition to fraction skills, students’ arithmetic fluency was measured. Fidelity of intervention, social validity, and time-efficiency of the manipulatives were also investigated. Fourth- and fifth-grade participants (N= 115) from Southern Finland were assigned to VM and CM intervention groups. The intervention was implemented during six 45-minute lessons over 2 weeks. Results revealed that the CM group outperformed the VM group in fraction skills, which suggests that CM should be favored in fraction interventions.Peer reviewe

    Frontal Cortex Myo-Inositol Is Associated with Sleep and Depression in Adolescents : A Proton Magnetic Resonance Spectroscopy Study

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    Aim: This study used proton magnetic resonance spectroscopy (H-1 MRS) to evaluate the neurochemistry of the frontal cortex in adolescents with symptoms of sleep and depression. Methods: Nineteen non-medicated adolescent boys (mean age 16.0 years; 9 clinical cases with depression/sleep symptoms and 10 healthy controls) underwent H-1 MRS at 3 T. MR spectra were acquired from the anterior cingulate cortex (ACC), the dorsolateral prefrontal cortex, and frontal white matter. Concentrations of N-acetyl aspartate, total creatine, choline-containing compounds, total glutamine plus glutamate, and myo-inositol (mI) were compared in the 2 subgroups, and correlated with sleep and clinical measures in the total sample. Sleep was assessed with self-report questionnaires and ambulatory polysomnography recordings. Results: Concentrations of mI were lower in both frontal cortical regions among the depressed adolescents than in controls. No statistically significant differences in other metabolite concentrations were observed between the subgroups. Frontal cortex mI concentrations correlated negatively with depression severity, subjective daytime sleepiness, insomnia symptoms, and the level of anxiety, and correlated positively with total sleep time and overall psychosocial functioning. The correlations between mI in the ACC and total sleep time as well as daytime sleepiness remained statistically significant when depression severity was controlled in the analyses. Conclusion: Lower frontal cortex ml may indicate a disturbed second messenger system. Frontal cortical mI may thus be linked to the pathophysiology of depression and concomitant sleep symptoms among maturing adolescents. Short sleep and daytime sleepiness may be associated with frontal cortex mI independently from depression. (C) 2017 S. Karger AG, BaselPeer reviewe

    Identifying childhood movement profiles and comparing differences in mathematical skills between clusters : A latent profile analysis

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    The aims of this study were; 1) to identify different movement profiles in sixth graders, and 2) to investigate if there are differences in their mathematical basic (BasicMath) and problem solving (ProbSol) skills between existing movement profiles. The sample included 461 (223 girls, 238 boys) students with a mean age of 11.27 +/- .32 years from southern and middle Finland. A latent profile analysis (LPA) revealed four movement profiles: "poor movers", "average movers", "skilled movers" and "expert movers". These profiles differed substantially in their motor competence (MC) and health-related fitness (HRF). A multivariate analysis of variance (MANOVA) also revealed that "poor movers" and "average movers" obtained lower results in BasicMath comparing with "skilled movers". The results of this study suggest that cardiorespiratory and muscular fitness, MC and BasicMath are interrelated.Peer reviewe

    Effects of Gender on Basic Numerical and Arithmetic Skills : Pilot Data From Third to Ninth Grade for a Large-Scale Online Dyscalculia Screener

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    In this study, we analyzed the development and effects of gender on basic number skills from third to ninth grade in Finland. Because the international comparison studies have shown slightly different developmental trends in mathematical attainment for different language groups in Finland, we added the language of education as a variable in our analysis. Participants were 4,265 students from third to ninth grade in Finland, representing students in two national languages (Finnish, n = 2,833, and Swedish, n = 1,432). Confirmatory factor analyses showed that the subtasks in the dyscalculia screener formed two separate factors, namely, number-processing skills and arithmetic fluency. We found a linear development trend across age cohorts in both the factors. Reliability and validity evidence of the measures supported the use of these tasks in the whole age group from 9 to15 years. In this sample, there was an increasing gender difference in favor of girls and Swedish-speaking students by grade levels in number-processing skills. At the same time, boys showed a better performance and a larger variance in tasks measuring arithmetic fluency. The results indicate that the gender ratio within the group with mathematical learning disabilities depends directly on tasks used to measure their basic number skills.Peer reviewe

    Epigenetic dysregulation of genes related to synaptic long-term depression among adolescents with depressive disorder and sleep symptoms

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    Funding Information: Financial support for the study includes a special federal grant ( TYH 2013342 ) to T.P. and funding from the Academy of Finland (grant number 276612 to A.S.U. and number 290039 to T.P.), Emil Aaltonen Foundation , Finnish Medical Foundation , Finnish Brain Foundation , Orion-Farmos Research Foundation , Päivikki and Sakari Sohlberg Foundation , and the Foundation for Psychocultural Research . We also wish to thank Auli Toivola for her valuable contribution regarding laboratory work. Publisher Copyright: © 2019 Elsevier B.V.Objectives: This study aimed to test the hypothesis that sleep and depression have independent effects on brain development and plasticity in adolescents, and that these changes are reflected in changes in the epigenome. Methods: Participants were 17 medication-free adolescent boys (age 16.05 +/- 0.80 years, mean +/- standard deviation (SD); eight cases with depression and sleep symptoms, nine healthy controls). Sleep was assessed by polysomnography recordings and the Pediatric Daytime Sleepiness Scale (PDSS) and Athens Insomnia Scale (AIS). Participants underwent a clinical evaluation. DNA methylation of blood leukocytes was measured by Illumina 450K array, and Ingenuity Pathway analysis was applied to identify the most significant pathways with differentially methylated positions (DMPs). Secondary analysis of the identified loci included linear correlations between methylation and the subjectively rated scales of sleep, depression and sleep microarchitecture. Results: Due to small sample size, we found no genome-wide significant differences in methylation between cases and controls. However, pathway analysis identified the synaptic long-term depression (LTD) canonical pathway (p = 0.00045) when the best 500 DMPs from the original case-control design were included. A flattened dissipation of slow wave sleep, tiredness and depression severity values correlated with five of 10 sites from the LTD pathway (IGF1R, PLAG16, PLA2R1, PPP2C5 and ERK12) in the secondary analysis when the case-control status was controlled for. Conclusion: Among adolescents, depressive disorder with sleep symptoms is associated with a distinctive epigenetic pattern of DNA methylation in blood leukocytes. The enrichment of DMPs on genes related to synaptic LTD emphasizes the role of sleep in synaptic plasticity and the widespread physiological consequences of disturbed sleep. (C) 2019 Elsevier B.V. All rights reserved.Peer reviewe

    Effects of Gender on Basic Numerical and Arithmetic Skills: Pilot Data From Third to Ninth Grade for a Large-Scale Online Dyscalculia Screener

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    In this study, we analyzed the development and effects of gender on basic number skills from third to ninth grade in Finland. Because the international comparison studies have shown slightly different developmental trends in mathematical attainment for different language groups in Finland, we added the language of education as a variable in our analysis. Participants were 4,265 students from third to ninth grade in Finland, representing students in two national languages (Finnish, n = 2,833, and Swedish, n = 1,432). Confirmatory factor analyses showed that the subtasks in the dyscalculia screener formed two separate factors, namely, number-processing skills and arithmetic fluency. We found a linear development trend across age cohorts in both the factors. Reliability and validity evidence of the measures supported the use of these tasks in the whole age group from 9 to15 years. In this sample, there was an increasing gender difference in favor of girls and Swedish-speaking students by grade levels in number-processing skills. At the same time, boys showed a better performance and a larger variance in tasks measuring arithmetic fluency. The results indicate that the gender ratio within the group with mathematical learning disabilities depends directly on tasks used to measure their basic number skills.</p
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