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Paul Wilhelm Dierkes

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Research article
Published: 04 June 2021 in Environmental Education Research
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In the past decades, zoos have increasingly developed into conservation and education centers and today make an important contribution to environmental education. In this context, this study investigated which factors influence attitudes towards species conservation. The variables examined were gender, age, the number of visits to zoos in the last 12 months, perception of zoos, interest in animals and the country where the survey was conducted. A total of 3347 participants in seven different countries were surveyed. In the hierarchical multiple regression, it was found that all the variables examined were significant influencing factors with exception of gender. A mediator analysis provided evidence that the number of visits to zoos, in addition to the direct effect on attitudes towards species conservation, also has a relevant indirect effect with interest in animals as mediators. Significant differences in attitudes towards species conservation were found between some of the countries studied, but only with a small effect sizes. Graphical Abstract

ACS Style

Matthias Winfried Kleespies; Natalia Álvarez Montes; Alina Miriam Bambach; Eva Gricar; Volker Wenzel; Paul Wilhelm Dierkes. Identifying factors influencing attitudes towards species conservation – a transnational study in the context of zoos. Environmental Education Research 2021, 1 -19.

AMA Style

Matthias Winfried Kleespies, Natalia Álvarez Montes, Alina Miriam Bambach, Eva Gricar, Volker Wenzel, Paul Wilhelm Dierkes. Identifying factors influencing attitudes towards species conservation – a transnational study in the context of zoos. Environmental Education Research. 2021; ():1-19.

Chicago/Turabian Style

Matthias Winfried Kleespies; Natalia Álvarez Montes; Alina Miriam Bambach; Eva Gricar; Volker Wenzel; Paul Wilhelm Dierkes. 2021. "Identifying factors influencing attitudes towards species conservation – a transnational study in the context of zoos." Environmental Education Research , no. : 1-19.

Journal article
Published: 01 April 2021 in Journal of Zoological and Botanical Gardens
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Locating a vocalizing animal can be useful in many fields of bioacoustics and behavioral research, and is often done in the wild, covering large areas. In zoos, however, the application of this method becomes particularly difficult, because, on the one hand, the animals are in a relatively small area and, on the other hand, reverberant environments and background noise complicate the analysis. Nevertheless, by localizing and analyzing animal sounds, valuable information on physiological state, sex, subspecies, reproductive state, social status, and animal welfare can be gathered. Therefore, we developed a sound localization software that is able to estimate the position of a vocalizing animal precisely, making it possible to assign the vocalization to the corresponding individual, even under difficult conditions. In this study, the accuracy and reliability of the software is tested under various conditions. Different vocalizations were played back through a loudspeaker and recorded with several microphones to verify the accuracy. In addition, tests were carried out under real conditions using the example of the giant otter enclosure at Dortmund Zoo, Germany. The results show that the software can estimate the correct position of a sound source with a high accuracy (median of the deviation 0.234 m). Consequently, this software could make an important contribution to basic research via position determination and the associated differentiation of individuals, and could be relevant in a long-term application for monitoring animal welfare in zoos.

ACS Style

Sebastian Schneider; Paul Dierkes. Localize Animal Sound Events Reliably (LASER): A New Software for Sound Localization in Zoos. Journal of Zoological and Botanical Gardens 2021, 2, 146 -163.

AMA Style

Sebastian Schneider, Paul Dierkes. Localize Animal Sound Events Reliably (LASER): A New Software for Sound Localization in Zoos. Journal of Zoological and Botanical Gardens. 2021; 2 (2):146-163.

Chicago/Turabian Style

Sebastian Schneider; Paul Dierkes. 2021. "Localize Animal Sound Events Reliably (LASER): A New Software for Sound Localization in Zoos." Journal of Zoological and Botanical Gardens 2, no. 2: 146-163.

Research article
Published: 05 March 2021 in Zoo Biology
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Upon a drastic decline of the giraffe population in the wild, conservation efforts and therefore the role of zoos have become more important than ever. With their unique opportunities, zoos provide excellent conditions to study animal behavior, expanding the knowledge about the giraffe's behavior repertoire and their ability to adapt. This study therefore examined the nocturnal behavior of 63 giraffe living in 13 different EAZA zoos across Germany and the Netherlands. Giraffe were observed and videos recorded via infrared sensitive cameras during the winter seasons 2015–2018. The observation period spanned nightly from 17:00 to 7:00. Thus, 198 nights, with a total of 2772 h were recorded and analyzed. Linear mixed models were then used to assess potential biological and environmental factors influencing behavior during the dark phase. Results show that individual variables such as age, subspecies and motherhood determined nocturnal activity and sleep behavior most. Among the variables studied, husbandry conditions and environmental factors complying with EAZA standards had no influence on the giraffe's nocturnal behavior. By combining nocturnal activity analyses and an assessment of potential influencing factors, our findings present a holistic approach to a better understanding of captive giraffe behavior and allow for management implications.

ACS Style

Anna Lena Burger; Johannes Hartig; Paul W. Dierkes. Biological and environmental factors as sources of variation in nocturnal behavior of giraffe. Zoo Biology 2021, 40, 171 -181.

AMA Style

Anna Lena Burger, Johannes Hartig, Paul W. Dierkes. Biological and environmental factors as sources of variation in nocturnal behavior of giraffe. Zoo Biology. 2021; 40 (3):171-181.

Chicago/Turabian Style

Anna Lena Burger; Johannes Hartig; Paul W. Dierkes. 2021. "Biological and environmental factors as sources of variation in nocturnal behavior of giraffe." Zoo Biology 40, no. 3: 171-181.

Journal article
Published: 06 February 2021 in Sustainability
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The human-nature connection is an important factor that is frequently the subject of environmental education research and environmental psychology. Therefore, over the years, numerous measuring instruments have been established to quantitatively record a person’s connection to nature. However, there is no instrument specifically for children with cognitive limitations. For this reason, in this study, an established scale for connection to nature, the inclusion of nature in self scale (INS), was modified especially for the needs of this group. Study 1 investigated what students understand by the term “nature” in order to create an illustrated version of the INS. In study 2, the new instrument was tested on university students and compared with the original INS and the connectedness to nature scale (CNS). No significant differences between the original INS and the new developed scale were found (p = 0.247), from which it can be concluded that the illustrated INS (IINS) measures the connection to nature with similar accuracy as the original INS. In study 3, the instrument was tested together with other established nature connection instruments on the actual target group, students with disabilities. The correlation between the IINS, the CNS, and nature connectedness scale (NR) were in accordance with the expected literature values (rIINS-CNS = 0.570 & rIINS-NR = 0.605). The results of this study also prove effectiveness of the developed illustrated scale. This research thus provides a suitable measuring instrument for people with learning difficulties and can make a contribution to the investigation of human-nature connections and conservation education.

ACS Style

Matthias Kleespies; Tina Braun; Paul Dierkes; Volker Wenzel. Measuring Connection to Nature—A Illustrated Extension of the Inclusion of Nature in Self Scale. Sustainability 2021, 13, 1761 .

AMA Style

Matthias Kleespies, Tina Braun, Paul Dierkes, Volker Wenzel. Measuring Connection to Nature—A Illustrated Extension of the Inclusion of Nature in Self Scale. Sustainability. 2021; 13 (4):1761.

Chicago/Turabian Style

Matthias Kleespies; Tina Braun; Paul Dierkes; Volker Wenzel. 2021. "Measuring Connection to Nature—A Illustrated Extension of the Inclusion of Nature in Self Scale." Sustainability 13, no. 4: 1761.

Sociology
Published: 05 November 2020 in PLOS ONE
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The new concept of relational values (RVs) is gaining more and more attention in environmental research, but empirical analyses are still rare. However, this type of research is necessary because the RVs have an influence on environmental behavior. To evaluate the impact of biological education on attributing higher importance to RVs and connectedness to nature, we compared the connection to nature scores (using the inclusion of nature scale (INS) and connectedness to nature scale (CNS)) and RV scores of biologically interested high school students (n = 417) with first year (n = 593) and advanced biology (n = 223) students. While high school students showed significant lower connection to nature scores than university students, there was no significant difference in RVs between the test groups. These results suggest that there is a lack of factors in the university study of biology that can change RVs. The gender comparison of RVs and connection to nature showed a significant higher RV score for females while INS and CNS did not show a gender difference. Thus, the study makes an important contribution to the research, as it was able to prove that gender has an influence on a person's RVs but not on their connection to nature.

ACS Style

Matthias Winfried Kleespies; Paul Wilhelm Dierkes. Impact of biological education and gender on students’ connection to nature and relational values. PLOS ONE 2020, 15, e0242004 .

AMA Style

Matthias Winfried Kleespies, Paul Wilhelm Dierkes. Impact of biological education and gender on students’ connection to nature and relational values. PLOS ONE. 2020; 15 (11):e0242004.

Chicago/Turabian Style

Matthias Winfried Kleespies; Paul Wilhelm Dierkes. 2020. "Impact of biological education and gender on students’ connection to nature and relational values." PLOS ONE 15, no. 11: e0242004.

Journal article
Published: 22 May 2020 in Sustainability
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The UN's sustainable development goals (SDGs), which aim to solve important economic, social, and environmental problems of humanity, are to be supported by education for sustainable development (ESD). Empirical studies on the success of the implementation of the SDGs in the field of education are still pending. For this reason, using the loss of global biodiversity as an example, this study examined the extent to which high school students, teacher trainees in biology, and biology bachelor students can identify the causes of the global biodiversity loss. A new questioning tool was developed and tested on 889 participants. In addition, the relationship between connection to nature and the personal assessment about biodiversity threats was examined. The factor analysis of the scale used showed that 11 out of 16 items were assigned to the intended factor. The comparison between high school students, teacher trainees in biology, and biology bachelor students showed no significant difference in overall assessment of the reasons for global biodiversity loss. When comparing the three risk levels in which the risk factors for biodiversity could be divided, across the three student groups, only minor differences were found. Therefore, a specific education of prospective teachers is necessary, as they have to pass on the competence as multipliers to their students. No significant difference could be found when examining the relationship between connection to nature and the overall scores of the assessment scale for the reasons of biodiversity loss. However, it was found that people who felt more connected to nature were more capable of assessing the main causes of risk for global biodiversity, while people who felt less connected to nature achieved better scores for the medium factors.

ACS Style

Matthias Winfried Kleespies; Paul Wilhelm Dierkes. Personal Assessment of Reasons for the Loss of Global Biodiversity—an Empirical Analysis. Sustainability 2020, 12, 4277 .

AMA Style

Matthias Winfried Kleespies, Paul Wilhelm Dierkes. Personal Assessment of Reasons for the Loss of Global Biodiversity—an Empirical Analysis. Sustainability. 2020; 12 (10):4277.

Chicago/Turabian Style

Matthias Winfried Kleespies; Paul Wilhelm Dierkes. 2020. "Personal Assessment of Reasons for the Loss of Global Biodiversity—an Empirical Analysis." Sustainability 12, no. 10: 4277.

Journal article
Published: 14 May 2020 in Applied Animal Behaviour Science
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The interaction of internal clocks and environmental conditions determines the daily behavioural rhythm of an animal. Due to the strong influence of light, these circadian rhythms oscillate in mammals over a cycle length of about 24 h, equivalent to the daily light-dark cycle. The relation between activity and rest within this cycle is species-specific and age dependent. Since strong deviations from existing rhythms can harm health seriously, the observation of animal behaviour using activity budgets is a common tool to assess welfare. This study therefore investigated the nightly activity budget of 63 giraffe (Giraffa camelopardalis) from 13 EAZA institutions. The nightly behaviour was recorded and analysed in the winter seasons 2015–2018 over an observation period from 17:00 to 7:00 h for 10–14 nights, using infrared sensitive cameras. To analyse rest-activity rhythms of three age classes of giraffe during the dark phase of the night, linear mixed models were applied. Our results show that activity increases with increasing age of giraffe. Differences between age classes were further found for the time spent on rapid eye movement (REM) sleep, with juvenile and sub-adult giraffe spending more time in this specific state than adults. Analyses of behavioural rhythmicity indicated a rest-activity cycle length of about four hours, with age determining the rhythmic curve. Overall, this large-scale study confirms a strong age effect for both the nocturnal activity budget and the rest-activity rhythm in giraffe. The results of this study provide an important contribution to the continuous improvement of husbandry and management for zoo housed giraffe.

ACS Style

Anna Lena Burger; Johannes Hartig; Paul W. Dierkes. Shedding light into the dark: Age and light shape nocturnal activity and sleep behaviour of giraffe. Applied Animal Behaviour Science 2020, 229, 105012 .

AMA Style

Anna Lena Burger, Johannes Hartig, Paul W. Dierkes. Shedding light into the dark: Age and light shape nocturnal activity and sleep behaviour of giraffe. Applied Animal Behaviour Science. 2020; 229 ():105012.

Chicago/Turabian Style

Anna Lena Burger; Johannes Hartig; Paul W. Dierkes. 2020. "Shedding light into the dark: Age and light shape nocturnal activity and sleep behaviour of giraffe." Applied Animal Behaviour Science 229, no. : 105012.

Original research article
Published: 13 March 2020 in Frontiers in Psychology
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In recent environmental research, relational values (RVs) have emerged as a new group of values to explain environmental behavior. Although this new concept is attracting attention, empirical studies on the subject are still rare. On this basis, we have conducted three studies to analyze an existing measurement tool for RVs and compared the construct with the concept of connection to nature. In study 1, we confirmed convergent and discriminant validity of the RV scale by comparing it with the Two Factor Model of Environmental Values (2-MEV) model using a sample of n = 350 university students. Additionally, study 1 verified reliability using test–retest reliability on three different groups of students (n1 = 53; n2 = 37; n3 = 48). In study 2, principal component analyses were performed to examine the structure of RVs and to compare it to the concept of connection to nature by reusing the sample 350 university students from study 1. The results show that RVs and connection to nature are not fundamentally distinct constructs, but overlap. However, if the structure of the RV measurement is forced to a single factor, no perfect fit is found, making a multidimensional solution more likely. A third study was conducted to review the results from study 2 using confirmatory factor analysis on a new sample of 878 university and high school students. Study 3 confirmed RVs as a multidimensional construct with three factors: care, community, and connection. It also proved the overlap of the connection to nature and RV concepts to some extent.

ACS Style

Matthias Winfried Kleespies; Paul Dierkes. Exploring the Construct of Relational Values: An Empirical Approach. Frontiers in Psychology 2020, 11, 1 .

AMA Style

Matthias Winfried Kleespies, Paul Dierkes. Exploring the Construct of Relational Values: An Empirical Approach. Frontiers in Psychology. 2020; 11 ():1.

Chicago/Turabian Style

Matthias Winfried Kleespies; Paul Dierkes. 2020. "Exploring the Construct of Relational Values: An Empirical Approach." Frontiers in Psychology 11, no. : 1.

Journal article
Published: 05 March 2020 in Zoo Biology
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The present study assessed the diurnal variation in salivary cortisol in captive African elephants during routine management (baseline) and in relation to a potential stressor (translocation) to evaluate to what extent acute stress may affect diurnal cortisol patterns. Under baseline conditions, we collected morning and afternoon saliva samples of 10 animals (three zoos) on different days in two study periods (n = 3-10 per animal, daytime and period). Under stress conditions, we sampled the transported cow (newcomer) and the two cows of the destination zoo before and after the transport in the morning and afternoon (n = 3-9 per animal, daytime and transport phase), as well as after the first introduction of the newcomer to the bull (n = 1 per animal). Cortisol was measured in unextracted samples by enzyme immunoassay. Under baseline conditions, we observed the expected diurnal variation with higher cortisol levels in the morning than in the afternoon. Under stress conditions, neither a significant difference between pre- and posttransport, nor between morning and afternoon levels was found. The percentage difference between morning and afternoon cortisol after the transport, however, was remarkably lower than before the transport in the newcomer potentially indicating a stress response to familiarization. Saliva samples taken immediately after the introduction of the newcomer to the bull revealed a marked cortisol increase. Our findings indicate that stressors may disturb the diurnal cortisol rhythm. Furthermore, provided that samples can be collected promptly, salivary cortisol is a useful minimally invasive measure of physiological stress in the African elephant.

ACS Style

Susan Hambrecht; Ann‐Kathrin Oerke; Michael Heistermann; Paul Wilhelm Dierkes. Diurnal variation of salivary cortisol in captive African elephants (Loxodonta africana) under routine management conditions and in relation to a translocation event. Zoo Biology 2020, 39, 186 -196.

AMA Style

Susan Hambrecht, Ann‐Kathrin Oerke, Michael Heistermann, Paul Wilhelm Dierkes. Diurnal variation of salivary cortisol in captive African elephants (Loxodonta africana) under routine management conditions and in relation to a translocation event. Zoo Biology. 2020; 39 (3):186-196.

Chicago/Turabian Style

Susan Hambrecht; Ann‐Kathrin Oerke; Michael Heistermann; Paul Wilhelm Dierkes. 2020. "Diurnal variation of salivary cortisol in captive African elephants (Loxodonta africana) under routine management conditions and in relation to a translocation event." Zoo Biology 39, no. 3: 186-196.

Original research
Published: 14 February 2020 in Ecology and Evolution
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This study presents the first findings on nocturnal behavior patterns of wild Angolan giraffe. We characterized their nocturnal behavior and analyzed the influence of ecological factors such as group size, season, and habitat use. Giraffe were observed using night vision systems and thermal imaging cameras on Okapuka Ranch, Namibia. A total of 77 giraffe were observed during 24 nights over two distinct periods—July–August 2016 (dry season) and February–March 2017 (wet season). Photoperiod had a marked influence on their activity and moving behavior. At dusk, giraffe reduced the time spent moving and increasingly lay down and slept at the onset of darkness. Body postures that likely correspond to rapid eye movement (REM) sleep posture (RSP) were observed 15.8 ± 18.3 min after giraffe sat down. Season had a significant effect with longer RSP phases during the dry season (dry: 155.2 ± 191.1 s, n = 79; wet: 85.8 ± 94.9 s, n = 73). Further analyses of the influence of social behavior patterns did not show an effect of group size on RSP lengths. When a group of giraffe spent time at a specific resting site, several individuals were alert (vigilant) while other group members sat down or took up RSP. Simultaneous RSP events within a group were rarely observed. Resting sites were characterized by single trees or sparse bushes on open areas allowing for good visibility in a relatively sheltered location.

ACS Style

Anna Lena Burger; Julian Fennessy; Stephanie Fennessy; Paul W. Dierkes. Nightly selection of resting sites and group behavior reveal antipredator strategies in giraffe. Ecology and Evolution 2020, 10, 2917 -2927.

AMA Style

Anna Lena Burger, Julian Fennessy, Stephanie Fennessy, Paul W. Dierkes. Nightly selection of resting sites and group behavior reveal antipredator strategies in giraffe. Ecology and Evolution. 2020; 10 (6):2917-2927.

Chicago/Turabian Style

Anna Lena Burger; Julian Fennessy; Stephanie Fennessy; Paul W. Dierkes. 2020. "Nightly selection of resting sites and group behavior reveal antipredator strategies in giraffe." Ecology and Evolution 10, no. 6: 2917-2927.

Article
Published: 18 September 2017 in Research in Science Education
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This research evaluates the development of three environmental knowledge dimensions of secondary school students after participation in a singular 1-day outdoor education programme. Applying a cross-national approach, system, action-related and effectiveness knowledge levels of students educated in Germany and Singapore were assessed before and after intervention participation. Correlations between single knowledge dimensions and behaviour changes due to the environmental education intervention were examined. The authors applied a pre-, post- and retention test design and developed a unique multiple-choice instrument. Results indicate significant baseline differences in the prevalence of the different knowledge dimensions between subgroups. Both intervention subsamples showed a low presence of all baseline knowledge dimensions. Action-related knowledge levels were higher than those of system and effectiveness knowledge. Subsample-specific differences in performed pro-environmental behaviour were also significant. Both experimental groups showed significant immediate and sustained knowledge increases in the three dimensions after programme participation. Neither of the two control cohorts showed any significant increase in any knowledge dimension. Effectiveness knowledge improved most. The amount of demonstrated environmental actions increased significantly in both intervention groups. Both control cohorts did not show shifts in environmental behaviour. Yet, only weak correlations between any knowledge dimension and behaviour could be found.

ACS Style

Tina Braun; Paul Dierkes. Evaluating Three Dimensions of Environmental Knowledge and Their Impact on Behaviour. Research in Science Education 2017, 49, 1347 -1365.

AMA Style

Tina Braun, Paul Dierkes. Evaluating Three Dimensions of Environmental Knowledge and Their Impact on Behaviour. Research in Science Education. 2017; 49 (5):1347-1365.

Chicago/Turabian Style

Tina Braun; Paul Dierkes. 2017. "Evaluating Three Dimensions of Environmental Knowledge and Their Impact on Behaviour." Research in Science Education 49, no. 5: 1347-1365.

Articles
Published: 03 June 2017 in Environmental Education Research
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This study employs a uniquely multi-factorial, large-scale design to investigate baseline differences and the effects of a singular outdoor educational program on environmental attitudes, knowledge and behavior among primary and secondary school students educated in four different countries. Statistical modelling approaches employed country of residence, age, nationality, sampling year, gender and urban/ rural habitation as predictor variables. Baseline scores were explained by a number of predictors but country of residence and rural-urban differences appeared as the most consistent explanatory variable for positive changes in attitude, knowledge and behavior. Given the nexus of political, social, natural and cultural data contained within the residence variable, we discuss the complex web of drivers that may influence environmental literacy and environmentally responsible behavior. Spatial variation in the value of outdoor education programs is also discussed.

ACS Style

Tina Braun; Richard Cottrell; Paul Dierkes. Fostering changes in attitude, knowledge and behavior: demographic variation in environmental education effects. Environmental Education Research 2017, 24, 899 -920.

AMA Style

Tina Braun, Richard Cottrell, Paul Dierkes. Fostering changes in attitude, knowledge and behavior: demographic variation in environmental education effects. Environmental Education Research. 2017; 24 (6):899-920.

Chicago/Turabian Style

Tina Braun; Richard Cottrell; Paul Dierkes. 2017. "Fostering changes in attitude, knowledge and behavior: demographic variation in environmental education effects." Environmental Education Research 24, no. 6: 899-920.

Articles
Published: 03 August 2016 in Environmental Education Research
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Nature connectedness counts as a crucial predictor of pro-environmental behavior. For counteracting today’s environmental issues a successful re-connection of individuals to nature is necessary. Besides the promotion of knowledge transfer the aim of the educational program presented in this study is to connect students to their environment. This research explores the impact of an outdoor environmental education program on primary and secondary school students’ nature connectedness with regard to the extent of their nature experience and participant age. The intervention was implemented in two durations: one-day and five-days. Participants were divided into four subsamples from seven up to 18 years of age. Findings suggest that both intervention types evoke immediate shifts towards a stronger nature connectedness among students (p < .001). Notably, the five-day outdoor education interventions were significantly more effective in sustainably promoting nature connectedness compared to one-day field trips (p < .001). Seven to nine year old students performed the strongest shifts towards nature. The value of short-term and residential outdoor environmental education interventions is discussed.

ACS Style

Tina Braun; Paul Dierkes. Connecting students to nature – how intensity of nature experience and student age influence the success of outdoor education programs. Environmental Education Research 2016, 23, 937 -949.

AMA Style

Tina Braun, Paul Dierkes. Connecting students to nature – how intensity of nature experience and student age influence the success of outdoor education programs. Environmental Education Research. 2016; 23 (7):937-949.

Chicago/Turabian Style

Tina Braun; Paul Dierkes. 2016. "Connecting students to nature – how intensity of nature experience and student age influence the success of outdoor education programs." Environmental Education Research 23, no. 7: 937-949.

Journal article
Published: 20 March 2012 in Epilepsia
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Purpose: Despite the consistent observation that γ‐aminobutyric acid A (GABAA) receptors mediate excitatory responses at perinatal stages, the role of the GABAergic system in the generation of neonatal epileptiform activity remains controversial. Therefore, we analyzed whether tonic and phasic GABAergic transmission had differential effects on neuronal excitability during early development. Methods: We performed whole cell patch‐clamp and field potential recordings in the CA3 region of hippocampal slices from immature (postnatal day 4–7) rats to analyze the effect of specific antagonists and modulators of tonic and phasic GABAergic components on neuronal excitability. Key Findings: The GABAergic antagonists gabazine (3 μm) and picrotoxin (100 μm) induced epileptiform discharges, whereas activation of GABAA receptors attenuated epileptiform discharges. Under low‐Mg2+ conditions, 100 nm gabazine and 1 μm picrotoxin were sufficient to provoke epileptiform activity in 63.2% (n = 19) and 53.8% (n = 26) of the slices, respectively. Whole‐cell patch‐clamp experiments revealed that these concentrations significantly reduced the amplitude of phasic GABAergic postsynaptic currents but had no effect on tonic currents. In contrast, 1‐μm 4,5,6,7‐tetrahydroisoxaz‐olo[5,4‐c]‐pyridin‐3‐ol (THIP) induced a tonic current of −12 ± 2.5 pA (n = 6) and provoked epileptiform discharges in 57% (n = 21) of the slices. Significance: We conclude from these results that in the early postnatal rat hippocampus a constant phasic synaptic activity is required to control excitability and prevent epileptiform activity, whereas tonic GABAergic currents can mediate excitatory responses. Pharmacologic intervention at comparable human developmental stages should consider these ambivalent GABAergic actions.

ACS Style

Sergey N. Kolbaev; Salim Sharopov; Paul Dierkes; Heiko J. Luhmann; Werner Kilb. Phasic GABAA-receptor activation is required to suppress epileptiform activity in the CA3 region of the immature rat hippocampus. Epilepsia 2012, 53, 888 -896.

AMA Style

Sergey N. Kolbaev, Salim Sharopov, Paul Dierkes, Heiko J. Luhmann, Werner Kilb. Phasic GABAA-receptor activation is required to suppress epileptiform activity in the CA3 region of the immature rat hippocampus. Epilepsia. 2012; 53 (5):888-896.

Chicago/Turabian Style

Sergey N. Kolbaev; Salim Sharopov; Paul Dierkes; Heiko J. Luhmann; Werner Kilb. 2012. "Phasic GABAA-receptor activation is required to suppress epileptiform activity in the CA3 region of the immature rat hippocampus." Epilepsia 53, no. 5: 888-896.

Journal article
Published: 15 January 2012 in Journal of Experimental Biology
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SUMMARY The hyperpolarisation-activated cation current (Ih) has been described in many vertebrate and invertebrate species and cell types. In neurons, Ih is involved in rhythmogenesis, membrane potential stabilisation and many other functions. In this work, we investigate the distribution and functional properties of Ih in identified leech neurons of intact segmental ganglia. We found Ih in the mechanosensory touch (T), pressure (P) and noxious (N) neurons, as well as in Retzius neurons. The current displayed its largest amplitude in P neurons and we investigated its biophysical and pharmacological properties in these cells. Ih was half-maximally activated at –65 mV and fully activated at –100 mV. The current mutually depended on both Na+ and K+ with a permeability ratio pNa/pK of ∼0.21. The reversal potential was approximately –35 mV. The time course of activation could be approximated by a single time constant of ∼370 ms at –60 mV, but required two time constants at –80 mV of ∼80 and ∼560 ms. The current was half-maximally blocked by 0.3 mmol l–1 Cs+ but was insensitive to the bradycardic agent ZD7288. The physiological function of this channel could be a subtle alteration of the firing behaviour of mechanosensory neurons as well as a stabilisation of the resting membrane potential.

ACS Style

Ednan Gerard; Peter Hochstrate; Paul Dierkes; Philippe Coulon. Functional properties and cell type specific distribution of Ih channels in leech neurons. Journal of Experimental Biology 2012, 215, 227 -238.

AMA Style

Ednan Gerard, Peter Hochstrate, Paul Dierkes, Philippe Coulon. Functional properties and cell type specific distribution of Ih channels in leech neurons. Journal of Experimental Biology. 2012; 215 (2):227-238.

Chicago/Turabian Style

Ednan Gerard; Peter Hochstrate; Paul Dierkes; Philippe Coulon. 2012. "Functional properties and cell type specific distribution of Ih channels in leech neurons." Journal of Experimental Biology 215, no. 2: 227-238.

Book
Published: 16 February 2010 in Microelectronic Packaging
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Driven by the electronics industry, electrochemical technology has rapidly evolved, finding increasing applications in microelectronics, batteries, sensors, materials science, industrial fabrication, corrosion, microbiology, neurobiology and medicine. Electrochemical Microsystem Technologies provides an overview of the technological status; the development of micropatternings and micro-biosensors; and the applications of micropower with electrochemical microsystems.This book covers a wide spectrum of issues ranging from fundamental electrochemical processes to their applications in micro- and nanofabrication, microanalyses, microsensing, and their interaction with inorganic surfaces and biological systems. The editors provide comprehensive background to unique processes, such as the technological development of miniaturization, microfabrication, thin film deposition, etching, cleaning, planarization, and silicon processing technologies to introduce a wide range of applications in context. More than 40 internationally recognized industry, research, and medical experts provide insight on the current status and future trends in their fields. They also highlight the impact of applying electrochemical microsystem technologies on industries such as storage and packaging; microelectronics, sensors, and portable electronics; machining, polishing, anodization, and plating technologies in heavy industries; biosensing, biological implant technology, and neurobiology; and cross-disciplinary integrated systems.Electrochemical Microsystem Technologies is a valuable reference for graduate/postgraduate students, technologists, and researchers working in the field of electrochemical technology. Driven by the electronics industry, electrochemical technology has rapidly evolved, finding increasing applications in microelectronics, batteries, sensors, materials science, industrial fabrication, corrosion, microbiology, neurobiology and medicine. Electrochemical Microsystem Technologies provides an overview of the technological status; the development of micropatternings and micro-biosensors; and the applications of micropower with electrochemical microsystems.This book covers a wide spectrum of issues ranging from fundamental electrochemical processes to their applications in micro- and nanofabrication, microanalyses, microsensing, and their interaction with inorganic surfaces and biological systems. The editors provide comprehensive background to unique processes, such as the technological development of miniaturization, microfabrication, thin film deposition, etching, cleaning, planarization, and silicon processing technologies to introduce a wide range of applications in context. More than 40 internationally recognized industry, research, and medical experts provide insight on the current status and future trends in their fields. They also highlight the impact of applying electrochemical microsystem technologies on industries such as storage and packaging; microelectronics, sensors, and portable electronics; machining, polishing, anodization, and plating technologies in heavy industries; biosensing, biological implant technology, and neurobiology; and cross-disciplinary integrated systems.Electrochemical Microsystem Technologies is a valuable reference for graduate/postgraduate students, technologists, and researchers working in the field of electrochemical technology. Driven by the electronics industry, electrochemical technology has rapidly evolved, finding increasing applications in microelectronics, batteries, sensors, materials science, industrial fabrication, corrosion, microbiology, neurobiology and medicine. Electrochemical Microsystem Technologies provides an overview of the technological status; the development of micropatternings and micro-biosensors; and the applications of micropower with electrochemical microsystems.This book covers a wide spectrum of issues ranging from fundamental electrochemical processes to their applications in micro- and nanofabrication, microanalyses, microsensing, and their interaction with inorganic surfaces and biological systems. The editors provide comprehensive background to unique processes, such as the technological development of miniaturization, microfabrication, thin film deposition, etching, cleaning, planarization, and silicon processing technologies to introduce a wide range of applications in context. More than 40 internationally recognized industry, research, and medical experts provide insight on the current status and future trends in their fields. They also highlight the impact of applying electrochemical microsystem technologies on industries such as storage and packaging; microelectronics, sensors, and portable electronics; machining, polishing, anodization, and plating technologies in heavy industries; biosensing, biological implant technology, and neurobiology; and cross-disciplinary integrated systems.Electrochemical Microsystem Technologies is a valuable reference for graduate/postgraduate students, technologists, and researchers working in the field of electrochemical technology. Driven by the electronics industry, electrochemical technology has rapidly evolved, finding increasing applications in microelectronics, batteries, sensors, materials science, industrial fabrication, corrosion, microbiology, neurobiology and medicine. Electrochemical Microsystem Technologies provides an overview of the technological status; the development of micropatternings and micro-biosensors; and the applications of micropower with electrochemical microsystems.This book covers a wide spectrum of issues ranging from fundamental electrochemical processes to their applications in micro- and nanofabrication, microanalyses, microsensing, and their interaction with inorganic surfaces and biological systems. The editors provide comprehensive background to unique processes, such as the technological development of miniaturization, microfabrication, thin film...

ACS Style

Paul Wilhelm Dierkes; Susanne Neumann; Anja Müller; Dorothee Günzel; Wolf-Rüdiger Schlue. Multi-barrelled ion-selective microelectrodes. Microelectronic Packaging 2010, 526 -540.

AMA Style

Paul Wilhelm Dierkes, Susanne Neumann, Anja Müller, Dorothee Günzel, Wolf-Rüdiger Schlue. Multi-barrelled ion-selective microelectrodes. Microelectronic Packaging. 2010; ():526-540.

Chicago/Turabian Style

Paul Wilhelm Dierkes; Susanne Neumann; Anja Müller; Dorothee Günzel; Wolf-Rüdiger Schlue. 2010. "Multi-barrelled ion-selective microelectrodes." Microelectronic Packaging , no. : 526-540.

Journal article
Published: 15 February 2008 in Journal of Experimental Biology
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SUMMARY During periods of high activity neurons are expected to swell due to the uptake of Cl–. To find out whether leech Retzius neurons possess swelling-activated Cl– channels that facilitate Cl– efflux and, hence, volume recovery, we exposed the cells to hypotonic solutions. In hypotonic solutions, the cells slowly swelled but did not undergo a regulatory volume decrease. However, the cell volume increased less than predicted for an ideal osmometer, suggesting the action of a compensatory mechanism. The cell swelling was paralleled by a marked decrease in the input resistance as well as by the activation of a membrane current with a reversal potential close to the Cl–equilibrium potential. This current was substantially diminished by removing bath Cl–, by applying the Cl– channel blocker DIDS, or by treating the cells with the tubulin polymerization inhibitor colchicine. Furthermore, in the presence of colchicine or vinblastine, the cell swelling was substantially increased. It is concluded that leech Retzius neurons possess swelling-activated Cl–channels that require an intact microtubule system for activation. The channels may help to restore cell volume after periods of high neuronal activity.

ACS Style

Philippe Coulon; Hans-Joachim Wüsten; Peter Hochstrate; Paul Dierkes. Swelling-activated chloride channels in leech Retzius neurons. Journal of Experimental Biology 2008, 211, 630 -641.

AMA Style

Philippe Coulon, Hans-Joachim Wüsten, Peter Hochstrate, Paul Dierkes. Swelling-activated chloride channels in leech Retzius neurons. Journal of Experimental Biology. 2008; 211 (4):630-641.

Chicago/Turabian Style

Philippe Coulon; Hans-Joachim Wüsten; Peter Hochstrate; Paul Dierkes. 2008. "Swelling-activated chloride channels in leech Retzius neurons." Journal of Experimental Biology 211, no. 4: 630-641.

Comparative study
Published: 21 April 2006 in Journal of Neuroscience Research
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The osmolarity of the extracellular space (ECS) compartment is an important factor determining the excitability of neuronal tissue. In the adult hippocampus an important role of osmolarity and ECS diffusion parameters on the susceptibility to epileptic events is well established, but the influence of hypo‐ and hyperosmolar conditions on the immature hippocampus remains elusive. To investigate the influence of osmolarity on epileptiform activity, extracellular field potentials were recorded in the CA3 region of hippocampal slices of immature (postnatal days 4–7) Wistar rats. The ECS diffusion parameters were determined by the real‐time tetramethylammonium (TMA+) iontophoretic method with ion‐selective microelectrodes in immature hippocampal slices and showed a lack of diffusion anisotropy; a tortuosity of about 1.39; and a volume fraction, α, of 0.41 ± 0.01 (n = 10 slices). A reduction in osmolarity of –90 mOsm induced a decrease in α to 0.17 ± 0.02 (n = 4 slices). The frequency of epileptiform activity elicited in 10–50 μM 4‐AP‐containing low‐Mg2+ solution was increased under –90 mOsm and –40 mOsm hypoosmolar conditions by 39.9% ± 8.1% (n = 16) and 24.1% ± 4.8% (n = 10), respectively, whereas hyperosmolar solutions decreased the frequency. A –90‐mOsm reduction in the osmolarity of low‐Mg2+ solution induced epileptiform activity in nine of 19 slices. In summary, these results demonstrate that hypoosmolar conditions increased excitability and susceptibility to epileptiform activity in immature hippocampal slices, suggesting a functional role of the larger α in suppression of seizures.

ACS Style

Werner Kilb; Paul Dierkes; Eva Syková; Lydia Vargová; Heiko J. Luhmann. Hypoosmolar conditions reduce extracellular volume fraction and enhance epileptiform activity in the CA3 region of the immature rat hippocampus. Journal of Neuroscience Research 2006, 84, 119 -129.

AMA Style

Werner Kilb, Paul Dierkes, Eva Syková, Lydia Vargová, Heiko J. Luhmann. Hypoosmolar conditions reduce extracellular volume fraction and enhance epileptiform activity in the CA3 region of the immature rat hippocampus. Journal of Neuroscience Research. 2006; 84 (1):119-129.

Chicago/Turabian Style

Werner Kilb; Paul Dierkes; Eva Syková; Lydia Vargová; Heiko J. Luhmann. 2006. "Hypoosmolar conditions reduce extracellular volume fraction and enhance epileptiform activity in the CA3 region of the immature rat hippocampus." Journal of Neuroscience Research 84, no. 1: 119-129.

Journal article
Published: 10 December 2005 in Pflügers Archiv - European Journal of Physiology
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By using electrophysiological and microfluorimetric methods, we found that leech Retzius neurons swell after inhibition of the Na+–K+ pump by the cardiac glycoside ouabain. To explore the mechanism of this swelling, we measured the effect of ouabain on [Na+]i, [K+]i, and [Cl−]i, as well as on the membrane potential, by applying triple-barrelled ion-sensitive microelectrodes. As shown previously, ouabain induced a marked [Na+]i increase, a [K+]i decrease, and a membrane depolarization, and it also evoked an increase in [Cl−]i. The analysis of the data revealed a net uptake of NaCl, which quantitatively explained the ouabain-induced cell swelling. In the absence of extracellular Na+ or Cl−, NaCl uptake was excluded, and the cell volume remained unaffected. Likewise, NaCl uptake and, hence, cell swelling did not occur when the Na+–K+ pump was inhibited by omitting bath K+. Also, in K+-free solution, [Na+]i increased and [K+]i dropped, but [Cl−]i slightly decreased, and after an initial, small membrane depolarization, the cells hyperpolarized for a prolonged period. It is concluded that the ouabain-induced NaCl uptake is caused by the depolarization of the plasma membrane, which augments the inwardly directed electrochemical Cl− gradient.

ACS Style

Paul Wilhelm Dierkes; Hans Joachim Wüsten; Guido Klees; Anja Müller; Peter Hochstrate. Ionic mechanism of ouabain-induced swelling of leech Retzius neurons. Pflügers Archiv - European Journal of Physiology 2005, 452, 25 -35.

AMA Style

Paul Wilhelm Dierkes, Hans Joachim Wüsten, Guido Klees, Anja Müller, Peter Hochstrate. Ionic mechanism of ouabain-induced swelling of leech Retzius neurons. Pflügers Archiv - European Journal of Physiology. 2005; 452 (1):25-35.

Chicago/Turabian Style

Paul Wilhelm Dierkes; Hans Joachim Wüsten; Guido Klees; Anja Müller; Peter Hochstrate. 2005. "Ionic mechanism of ouabain-induced swelling of leech Retzius neurons." Pflügers Archiv - European Journal of Physiology 452, no. 1: 25-35.

Journal article
Published: 01 November 2005 in The Journal of Membrane Biology
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In leech P neurons the inhibition of the Na(+)-K(+) pump by ouabain or omission of bath K(+) leaves the membrane potential unaffected for a prolonged period or even induces a marked membrane hyperpolarization, although the concentration gradients for K(+) and Na(+) are attenuated substantially. As shown previously, this stabilization of the membrane potential is caused by an increase in the K(+) conductance of the plasma membrane, which compensates for the reduction of the K(+) gradient. The data presented here strongly suggest that the increased K(+) conductance is due to Na(+)-activated K(+) (K(Na)) channels. Specifically, an increase in the cytosolic Na(+) concentration ([Na(+)](i)) was paralleled by a membrane hyperpolarization, a decrease in the input resistance (R(in)) of the cells, and by the occurrence of an outwardly directed membrane current. The relationship between R(in) and [Na(+)](i) followed a simple model in which the R(in) decrease was attributed to K(+) channels that are activated by the binding of three Na(+) ions, with half-maximal activation at [Na(+)](i) between 45 and 70 mM. At maximum channel activation, R(in) was reduced by more than 90%, suggesting a significant contribution of the K(Na) channels to the physiological functioning of the cells, although evidence for such a contribution is still lacking. Injection experiments showed that the K(Na) channels in leech P neurons are also activated by Li(+).

ACS Style

G. Klees; P. Hochstrate; P.W. Dierkes. Sodium-dependent Potassium Channels in Leech P Neurons. The Journal of Membrane Biology 2005, 208, 27 -38.

AMA Style

G. Klees, P. Hochstrate, P.W. Dierkes. Sodium-dependent Potassium Channels in Leech P Neurons. The Journal of Membrane Biology. 2005; 208 (1):27-38.

Chicago/Turabian Style

G. Klees; P. Hochstrate; P.W. Dierkes. 2005. "Sodium-dependent Potassium Channels in Leech P Neurons." The Journal of Membrane Biology 208, no. 1: 27-38.