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The COVID-19 pandemic has affected schooling worldwide. In many places, schools closed for weeks or months, only part of the student body could be educated at any one time, or students were taught online. Previous research discloses the relevance of schooling for the development of cognitive abilities. We therefore compared the intelligence test performance of 424 German secondary school students in Grades 7 to 9 (42% female) tested after the first six months of the COVID-19 pandemic (i.e., 2020 sample) to the results of two highly comparable student samples tested in 2002 (n = 1506) and 2012 (n = 197). The results revealed substantially and significantly lower intelligence test scores in the 2020 sample than in both the 2002 and 2012 samples. We retested the 2020 sample after another full school year of COVID-19-affected schooling in 2021. We found mean-level changes of typical magnitude, with no signs of catching up to previous cohorts or further declines in cognitive performance. Perceived stress during the pandemic did not affect changes in intelligence test results between the two measurements.
Background
Identifying pain-related response patterns and understanding functional mechanisms of symptom formation and recovery are important for improving treatment.
Objectives
We aimed to replicate pain-related avoidance-endurance response patterns associated with the Fear-Avoidance Model, and its extension, the Avoidance-Endurance Model, and examined their differences in secondary measures of stress, action control (i.e., dispositional action vs. state orientation), coping, and health.
Methods
Latent profile analysis (LPA) was conducted on self-report data from 536 patients with chronic non-specific low back pain at the beginning of an inpatient rehabilitation program. Measures of stress (i.e., pain, life stress) and action control were analyzed as covariates regarding their influence on the formation of different pain response profiles. Measures of coping and health were examined as dependent variables.
Results
Partially in line with our assumptions, we found three pain response profiles of distress-avoidance, eustress-endurance, and low-endurance responses that are depending on the level of perceived stress and action control. Distress-avoidance responders emerged as the most burdened, dysfunctional patient group concerning measures of stress, action control, maladaptive coping, and health. Eustress-endurance responders showed one of the highest levels of action versus state orientation, as well as the highest levels of adaptive coping and physical activity. Low-endurance responders reported lower levels of stress as well as equal levels of action versus state orientation, maladaptive coping, and health compared to eustress-endurance responders; however, equally low levels of adaptive coping and physical activity compared to distress-avoidance responders.
Conclusions
Apart from the partially supported assumptions of the Fear-Avoidance and Avoidance-Endurance Model, perceived stress and dispositional action versus state orientation may play a crucial role in the formation of pain-related avoidance-endurance response patterns that vary in degree of adaptiveness. Results suggest tailoring interventions based on behavioral and functional analysis of pain responses in order to more effectively improve patients quality of life.
Food waste is the origin of major social and environmental issues. In industrial societies, domestic households are the biggest contributors to this problem. But why do people waste food although they buy and value it? Answering this question is mandatory to design effective interventions against food waste. So far, however, many interventions have not been based on theoretical knowledge. Integrating food waste literature and ambivalence research, we propose that domestic food waste can be understood via the concept of ambivalence—the simultaneous presence of positive and negative associations towards the same attitude object. In support of this notion, we demonstrated in three pre-registered experiments that people experienced ambivalence towards non-perishable food products with expired best before dates. The experience of ambivalence was in turn associated with an increased willingness to waste food. However, two informational interventions aiming to prevent people from experiencing ambivalence did not work as intended (Experiment 3). We hope that the outlined conceptualization inspires theory-driven research on why and when people dispose of food and on how to design effective interventions.
People are increasingly concerned about how meat affects the environment, human health, and animal welfare, yet eating and enjoying meat remains a norm. Unsurprisingly, many people are ambivalent about meat—evaluating it as both positive and negative. Here, we propose that meat-related conflict is multidimensional and depends on people’s dietary group: Omnivores’ felt ambivalence relates to multiple negative associations that oppose a predominantly positive attitude towards meat, and veg*ans’ ambivalence relates to various positive associations that oppose a predominantly negative attitude. A qualitative study (N = 235; German) revealed that omnivores and veg*ans experience meat-related ambivalence due to associations with animals, sociability, sustainability, health, and sensory experiences. To quantify felt ambivalence in these domains, we developed the Meat Ambivalence Questionnaire (MAQ). We validated the MAQ in four pre-registered studies using self-report and behavioral data (N = 3,485; German, UK, representative US). Both omnivores and veg*ans reported meat-related ambivalence, but with differences across domains and their consequences for meat consumption. Specifically, ambivalence was associated with less meat consumption in omnivores (especially sensory-/animal-based ambivalence) and more meat consumption in veg*ans (especially sensory-/socially-based ambivalence). Network analyses shed further light on the nomological net of the MAQ while controlling for a comprehensive set of determinants of meat consumption. By introducing the MAQ, we hope to provide researchers with a tool to better understand how ambivalence accompanies behavior change and maintenance.
The global spread of the coronavirus pandemic has particularly dramatic consequences for the lives of migrants and refugees living in already marginalised and restricted conditions, whose ongoing crisis is at risk of being overlooked. But refugees are not only extremely vulnerable and at risk of infection, as several reports show, quickly develop their own protection measures like the production of hygienic products, the publication of their situation and calls for action and help. Therefore, this paper aims to research the effects of the coronavirus crisis on refugees in camp settings with a special ethnographic focus on how refugees actively deal with this crisis and if they, through already developed resilience, are capable of adapting to the restrictions as well as inventing strategies to cope with the difficult situation. To account for the variety of refugee camps as well as the different living conditions due to their locality, history and national asylum politics, we will look at three different locations, namely refugee asylum homes in Germany, hotspots on the Greek islands as well as one refugee camp in Kenya. The main questions will be how, under structurally and institutionally framed conditions of power and victimisation in refugee camps, forms of agency are established, made possible or limited. The goal is to show which strategies refugees apply to cope with the enhanced restrictions and exclusion, how they act to protect themselves and others from the virus and how they present and reflect their situation during the coronavirus pandemic. Finally, this discussion offers a new perspective to consider refugees not only as vulnerable victims, but also as actively engaged individuals.
Finding behavioral parameterization for a 1-D water balance model by multi-criteria evaluation
(2019)
Evapotranspiration is often estimated by numerical simulation. However, to produce accurate simulations, these models usually require on-site measurements for parameterization or calibration. We have to make sure that the model realistically reproduces both, the temporal patterns of soil moisture and evapotranspiration. In this study, we combine three sources of information: (i) measurements of sap velocities; (ii) soil moisture; and (iii) expert knowledge on local runoff generation and water balance to define constraints for a “behavioral” forest stand water balance model. Aiming for a behavioral model, we adjusted soil moisture at saturation, bulk resistance parameters and the parameters of the water retention curve (WRC). We found that the shape of the WRC influences substantially the behavior of the simulation model. Here, only one model realization could be referred to as “behavioral”. All other realizations failed for a least one of our evaluation criteria: Not only transpiration and soil moisture are simulated consistently with our observations, but also total water balance and runoff generation processes. The introduction of a multi-criteria evaluation scheme for the detection of unrealistic outputs made it possible to identify a well performing parameter set. Our findings indicate that measurement of different fluxes and state variables instead of just one and expert knowledge concerning runoff generation facilitate the parameterization of a hydrological model.
Institutional and cultural determinants of speed of government responses during COVID-19 pandemic
(2021)
This article examines institutional and cultural determinants of the speed of government responses during the COVID-19 pandemic. We define the speed as the marginal rate of stringency index change. Based on cross-country data, we find that collectivism is associated with higher speed of government response. We also find a moderating role of trust in government, i.e., the association of individualism-collectivism on speed is stronger in countries with higher levels of trust in government. We do not find significant predictive power of democracy, media freedom and power distance on the speed of government responses.
Acute social and physical stress interact to influence social behavior: the role of social anxiety
(2018)
Stress is proven to have detrimental effects on physical and mental health. Due to different tasks and study designs, the direct consequences of acute stress have been found to be wide-reaching: while some studies report prosocial effects, others report increases in antisocial behavior, still others report no effect. To control for specific effects of different stressors and to consider the role of social anxiety in stress-related social behavior, we investigated the effects of social versus physical stress on behavior in male participants possessing different levels of social anxiety. In a randomized, controlled two by two design we investigated the impact of social and physical stress on behavior in healthy young men. We found significant influences on various subjective increases in stress by physical and social stress, but no interaction effect. Cortisol was significantly increased by physical stress, and the heart rate was modulated by physical and social stress as well as their combination. Social anxiety modulated the subjective stress response but not the cortisol or heart rate response. With respect to behavior, our results show that social and physical stress interacted to modulate trust, trustworthiness, and sharing. While social stress and physical stress alone reduced prosocial behavior, a combination of the two stressor modalities could restore prosociality. Social stress alone reduced nonsocial risk behavior regardless of physical stress. Social anxiety was associated with higher subjective stress responses and higher levels of trust. As a consequence, future studies will need to investigate further various stressors and clarify their effects on social behavior in health and social anxiety disorders.
Karl May wurde Ende des 19. Jahrhunderts zum Erfolgs- und Volksschriftsteller mit seinem Orient-Zyklus "Durch die Wüste". In Abgrenzung dazu stellt dieser Vortrag einige heute unbekannte Frauen vor, deren Reiseschilderungen sich so abenteuerlich lesen wie die Romane Karl Mays - allerdings mit dem entscheidenden Unterschied, dass ihre Reisen real, und nicht nur in der Phantasie, stattfanden. - Der Aufsatz gibt einen Vortrag der Verfasserin wieder, der an der Hochschule Darmstadt am 28.04.1989 gehalten wurde. rn
Der Vortrag zeigt das Spektrum auf, in dem Frauenreisen als eigenständige Kategorie der Literatur- und Medienwissenschaft etabliert wurde. Ohne den Fokus der Konfrontation mit der orientalischen Lebenswelt und der Exklusion der Männer in bestimmten Lebensbereichen hätte sich diese Form von Reiseberichten nicht etablieren können.
Was ist Reiseliteratur? Mit diesem vagen und historisch divergenten Begriff befasst sich dieser Artikel. Die literarische Dimension trifft, so die These, auf die historische Ankunft der Figur des Touristen und der Ausformung des Reisens als Massenphänomen im 19. Jahrhundert: ein Begriffswandel vom Reisenden zum Tourist
Ausgelotet wird in diesem Aufsatz das Spektrum der ästhetischen und technischen Entwicklung des ältesten Genres, das der Film hervorgebracht hat: der Reisefilm. Schwerpunkt der Analyse ist das Frühe Kino und dessen filmästhetische Besonderheiten. rnNeue experimentelle Formen - wie die "Cartes postales Video" von Robert Cahen und filmkünstlerische Verwandlungen historischer Reisefilme durch die Mailänder Künstler Yervant Gianikian und Angela Ricci Lucchi - greifen zeitgenössisch auf dieses kreative Potential der Frühzeit des Kinos zurück. rn
Der Aufsatz, aus Anlaß der Ausstellung "Film-Ansichten aus der Ferne" im Düsseldorfer Filmmuseum und in dessen Auftrag entstanden, behandelt die Anfänge des Filmtourismus. rn1895 betrat der Film die Bühne der Reisemedien und begann, dem klassischen medialen Repertoire " von der Reisebeschreibung in Wort, Gemälde, Zeichnung bis hin zur Reisephotographie und dem steroskopischen Kaiser-Panorama " Konkurrenz zu machen. rnBesonders erfolgversprechend war jene topographische Bezugsgrösse, die auch schon in den tradierteren Medien massenmediale Quantität garantiert hatte: der "Orient" zwischen Maghreb und Ägypten.
Der Aufsatz erschien in der Zeitschrift "Deutschunterricht" 1994, zu einem Zeitpunkt, als über die Dominanz der visuellen Bilder und die Reizüberflutung durch das Fernsehen, das massenhaft und rastlos konsumierte Medium, allerorten diskutiert wurde. Er setzt sich mit der zentralten These von Neil Postman auseinander, in der Bilder per se als dumm eingestuft wurden, und seziert die Logik der notorischen Fernsehkritiker.
Zur Sache Schätzchen
(2005)
"Triumph der Bilder"
(2004)
Rundfunkmanuskript - gesendet in der Reihe "Reisen damals " vom Norddeutschen Rundfunk. Der Reisebericht von Louise Mühlbach über ihre Reise nach Ägypten, veröffentlicht 1871, ist mittlerweile online nachzulesen unter https://babel.hathitrust.org/cgi/pt?id=njp.32101012484679;view=1up;seq=140. Sprecherin des Beitrages war Evelyn Hamann.
Rezensiert wird das umfangreiche Buch von Matthias Steinle, das die wechselseitige Darstellung der Bundesrepublik Deutschland und der Deutschen Demokratischen Republik in Dokumentarfilmen analysiert. Die Materialauswahl umfasst mehr als 60 Filme, wobei der Begriff von Dokumentarfilm weit gefasst ist und auch Kino-Wochenschauen berücksichtigt werden,
Rezension des 21. Bandes der Gesellschaft für Exilforschung, der sich unter dem Titel "Film und Fotografie" mit der Exilsituation in der NS-Zeit auseinandersetzt. Der Sammelband stellt unbekannte Emigranten-Schicksale aus dem Bereich Film vor, fünf Beiträge befassen sich mit der Fotografie während und nach der NS-Zeit.
Heinz Piontek
(1986)
Der Aufsatz umreißt die Konkurrenz auf kulturpolitischem Gebiet zwischen den beiden deutschen Staaten. Im Zentrum steht das neu erfundene Genre des Indianerfilms, das sich aus DDR-Sicht deutlich von den populären Karl-May-Filmen des Westens absetzen wollte. Leider mußte aus Kostengründen weitgehend auf Abbildungen verzichtet werden.
Wie geht die Medieninstitution Fernsehen mit ihrem Sendematerial um? Und wie kommt es zu der Etablierung von Fernsehsendungen, die für sich in Anspruch nehmen können, Klassiker des deutschen Fernsehens geworden zu sein und damit einen Platz im kollektiven Gedächtnis der Nation beanspruchen? Diesen Fragen geht der Artikel, der als Einleitung zu dem Buch "Fernsehklassiker"(Alfeld: Coppi, 1998 [Aufsätze zu Film und Fernsehen Bd. 61]) verfaßt wurde, nach.
Der Aufsatz ist eine launige Hommage an das Frühe Kino. Er lässt die zeitgenössischen Quellen sprechen, die belegen, wie in den Pionierjahren des Films, vor dem Ersten Weltkrieg, das Ereignis "Kino" wahrgenommen wurde. Erinnert wird somit an einen Abschnitt der Filmgeschichte, der zu unrecht vergessen wurde bzw. ein Schattendasein führt - gemessen am nachfolgenden Schema der Langfilme und der zivilisierten Lichtspieltheater.
Der Hauptmann von Koepenick
(2005)
Im Zentrum dieses Aufsatzes steht der Spielfilm "Lisbon Story" (Deutschland / Portugal 1994/1995) des Filmregisseurs Wim Wenders. Es werden aber auch die früheren Arbeiten wie "Alice in den Städten" (BR Deutschland 1973/1974) und "Im Lauf der Zeit" (BR Deutschland 1975/1976) herangezogen, denn Kinder spielen in Wenders Spielfilmen eine bedeutende Rolle.
Der Aufsatz analysiert den Film "Karl May" von Hans Jürgen Syberberg, welcher am 18.10.1974 in München uraufgeführt wurde. Der Film bildet den mittleren Teil der Film-Trilogie, die Syberberg mit "Ludwig " Requiem für einen jungfräulichen König" begonnen und mit "Hitler, ein Film aus Deutschland" abgeschlossen hatte. Die Filmbiografie "Karl May", produziert von Bernd Eichinger und finanziert von der TMS Film GmbH (München) sowie Zweites Deutsches Fernsehen (ZDF) (Mainz), stellt den alternden Schriftsteller Karl May, gespielt von Helmut Käutner, in den Mittelpunkt - einen Autor, der sich an seinen eigenen Legenden psychisch abarbeitete und nach literarischer Anerkennung strebte. rn- Der Aufsatz gibt einen Vortrag wieder, der von Annette Deeken auf einer Tagung der Karl May-Gesellschaft am 1. Oktober 1983 in Regensburg gehalten wurde.
Laboratory landslide experiments enable the observation of specific properties of these natural hazards. However, these observations are limited by traditional techniques: frequently used high-speed video analysis and wired sensors (e.g. displacement). These techniques lead to the drawback that either only the surface and 2D profiles can be observed or wires confine the motion behaviour. In contrast, an unconfined observation of the total spatiotemporal dynamics of landslides is needed for an adequate understanding of these natural hazards.
The present study introduces an autonomous and wireless probe to characterize motion features of single clasts within laboratory-scale landslides. The Smartstone probe is based on an inertial measurement unit (IMU) and records acceleration and rotation at a sampling rate of 100 Hz. The recording ranges are ±16 g (accelerometer) and ±2000∘ s−1 (gyroscope). The plastic tube housing is 55 mm long with a diameter of 10 mm. The probe is controlled, and data are read out via active radio frequency identification (active RFID) technology. Due to this technique, the probe works under low-power conditions, enabling the use of small button cell batteries and minimizing its size.
Using the Smartstone probe, the motion of single clasts (gravel size, median particle diameter d50 of 42 mm) within approx. 520 kg of a uniformly graded pebble material was observed in a laboratory experiment. Single pebbles were equipped with probes and placed embedded and superficially in or on the material. In a first analysis step, the data of one pebble are interpreted qualitatively, allowing for the determination of different transport modes, such as translation, rotation and saltation. In a second step, the motion is quantified by means of derived movement characteristics: the analysed pebble moves mainly in the vertical direction during the first motion phase with a maximal vertical velocity of approx. 1.7 m s−1. A strong acceleration peak of approx. 36 m s−2 is interpreted as a pronounced hit and leads to a complex rotational-motion pattern. In a third step, displacement is derived and amounts to approx. 1.0 m in the vertical direction. The deviation compared to laser distance measurements was approx. −10 %. Furthermore, a full 3D spatiotemporal trajectory of the pebble is reconstructed and visualized supporting the interpretations. Finally, it is demonstrated that multiple pebbles can be analysed simultaneously within one experiment. Compared to other observation methods Smartstone probes allow for the quantification of internal movement characteristics and, consequently, a motion sampling in landslide experiments.
The study analyzes the long-term trends (1998–2019) of concentrations of the air pollutants ozone (O3) and nitrogen oxides (NOx) as well as meteorological conditions at forest sites in German midrange mountains to evaluate changes in O3 uptake conditions for trees over time at a plot scale. O3 concentrations did not show significant trends over the course of 22 years, unlike NO2 and NO, whose concentrations decreased significantly since the end of the 1990s. Temporal analyses of meteorological parameters found increasing global radiation at all sites and decreasing precipitation, vapor pressure deficit (VPD), and wind speed at most sites (temperature did not show any trend). A principal component analysis revealed strong correlations between O3 concentrations and global radiation, VPD, and temperature. Examination of the atmospheric water balance, a key parameter for O3 uptake, identified some unusually hot and dry years (2003, 2011, 2018, and 2019). With the help of a soil water model, periods of plant water stress were detected. These periods were often in synchrony with periods of elevated daytime O3 concentrations and usually occurred in mid and late summer, but occasionally also in spring and early summer. This suggests that drought protects forests against O3 uptake and that, in humid years with moderate O3 concentrations, the O3 flux was higher than in dry years with higher O3 concentrations.
Influence of Ozone and Drought on Tree Growth under Field Conditions in a 22 Year Time Series
(2022)
Studying the effect of surface ozone (O3) and water stress on tree growth is important for planning sustainable forest management and forest ecology. In the present study, a 22-year long time series (1998–2019) on basal area increment (BAI) and fructification severity of European beech (Fagus sylvatica L.) and Norway spruce (Picea abies (L.) H.Karst.) at five forest sites in Western Germany (Rhineland Palatinate) was investigated to evaluate how it correlates with drought and stomatal O3 fluxes (PODY) with an hourly threshold of uptake (Y) to represent the detoxification capacity of trees (POD1, with Y = 1 nmol O3 m−2 s−1). Between 1998 and 2019, POD1 declined over time by on average 0.31 mmol m−2 year−1. The BAI showed no significant trend at all sites, except in Leisel where a slight decline was observed over time (−0.37 cm2 per year, p < 0.05). A random forest analysis showed that the soil water content and daytime O3 mean concentration were the best predictors of BAI at all sites. The highest mean score of fructification was observed during the dry years, while low level or no fructification was observed in most humid years. Combined effects of drought and O3 pollution mostly influence tree growth decline for European beech and Norway spruce.
Formulations of macrocyclic lactone anthelmintics such as moxidectin are regularly administered to sheep to combat parasites. A disadvantage of these pharmaceuticals are their side effects on non-target organisms when entering the environment. Little is known about anthelmintic effects on plant reproduction and whether the effects depend on environmental factors. For ecological and methodological reasons, we aimed at testing whether temperature affects the efficacy of a common moxidectin-based formulation on seed germination. We carried out a germination experiment including three typical species of temperate European grasslands (Centaurea jacea, Galium mollugo, Plantago lanceolata). We applied three temperature regimes (15/5, 20/10, 30/20°C), and a four-level dilution series (1:100–1:800) of formulated moxidectin (i.e., Cydectin oral drench). These solutions represent seed-anthelmintic contacts in the digestive tract of sheep shortly after deworming. In addition, a control was carried out with purified water only. We regularly counted emerging seedlings and calculated final germination percentage, mean germination time and synchrony of germination. Formulated moxidectin significantly reduced percentage, speed and synchrony of germination. A 1:100 dilution of the formulation reduced germination percentage by a quarter and increased mean germination time by six days compared to the control. Temperature moderated effects of the anthelmintic drug on germination in all response variables and all species, but in different patterns and magnitudes (significant anthelmintic x temperature x species interactions). In all response variables, the two more extreme temperature regimes (15/5, 30/20°C) led to the strongest effects of formulated moxidectin. With respect to germination percentage, G. mollugo was more sensitive to formulated moxidectin at the warmest temperature regime, whereas P. lanceolata showed the highest sensitivity at the coldest regime. This study shows that it is important to consider temperature dependencies of the effects of pharmaceuticals on seed germination when conducting standardised germination experiments.
Background: Increasing exposure to engineered inorganic nanoparticles takes actually place in both terrestric and aquatic ecosystems worldwide. Although we already know harmful effects of AgNP on the soil bacterial community, information about the impact of the factors functionalization, concentration, exposure time, and soil texture on the AgNP effect expression are still rare. Hence, in this study, three soils of different grain size were exposed for up to 90 days to bare and functionalized AgNP in concentrations ranging from 0.01 to 1.00 mg/kg soil dry weight. Effects on soil microbial community were quantified by various biological parameters, including 16S rRNA gene, photometric, and fluorescence analyses.
Results: Multivariate data analysis revealed significant effects of AgNP exposure for all factors and factor combinations investigated. Analysis of individual factors (silver species, concentration, exposure time, soil texture) in the unifactorial ANOVA explained the largest part of the variance compared to the error variance. In depth analysis of factor combinations revealed even better explanation of variance. For the biological parameters assessed in this study, the matching of soil texture and silver species, and the matching of soil texture and exposure time were the two most relevant factor combinations. The factor AgNP concentration contributed to a lower extent to the effect expression compared to silver species, exposure time and physico–chemical composition of soil.
Conclusions: The factors functionalization, concentration, exposure time, and soil texture significantly impacted the effect expression of AgNP on the soil microbial community. Especially long-term exposure scenarios are strongly needed for the reliable environmental impact assessment of AgNP exposure in various soil types.
Climate change is expected to cause mountain species to shift their ranges to higher elevations. Due to the decreasing amounts of habitats with increasing elevation, such shifts are likely to increase their extinction risk. Heterogeneous mountain topography, however, may reduce this risk by providing microclimatic conditions that can buffer macroclimatic warming or provide nearby refugia. As aspect strongly influences the local microclimate, we here assess whether shifts from warm south-exposed aspects to cool north-exposed aspects in response to climate change can compensate for an upward shift into cooler elevations.
The microbial enzyme alkaline phosphatase contributes to the removal of organic phosphorus compounds from wastewaters. To cope with regulatory threshold values for permitted maximum phosphor concentrations in treated wastewaters, a high activity of this enzyme in the biological treatment stage, e.g., the activated sludge process, is required. To investigate the reaction dynamics of this enzyme, to analyze substrate selectivities, and to identify potential inhibitors, the determination of enzyme kinetics is necessary. A method based on the application of the synthetic fluorogenic substrate 4-methylumbelliferyl phosphate is proven for soils, but not for activated sludges. Here, we adapt this procedure to the latter. The adapted method offers the additional benefit to determine inhibition kinetics. In contrast to conventional photometric assays, no particle removal, e.g., of sludge pellets, is required enabling the analysis of the whole sludge suspension as well as of specific sludge fractions. The high sensitivity of fluorescence detection allows the selection of a wide substrate concentration range for sound modeling of kinetic functions.
- Fluorescence array technique for fast and sensitive analysis of high sample numbers
- No need for particle separation – analysis of the whole (diluted) sludge suspension
- Simultaneous determination of standard and inhibition kinetics
Amphibian diversity in the Amazonian floating meadows: a Hanski core-satellite species system
(2021)
The Amazon catchment is the largest river basin on earth, and up to 30% of its waters flow across floodplains. In its open waters, floating plants known as floating meadows abound. They can act as vectors of dispersal for their associated fauna and, therefore, can be important for the spatial structure of communities. Here, we focus on amphibian diversity in the Amazonian floating meadows over large spatial scales. We recorded 50 amphibian species over 57 sites, covering around 7000 km along river courses. Using multi-site generalised dissimilarity modelling of zeta diversity, we tested Hanski's core-satellite hypothesis and identified the existence of two functional groups of species operating under different ecological processes in the floating meadows. ‘Core' species are associated with floating meadows, while ‘satellite' species are associated with adjacent environments, being only occasional or accidental occupants of the floating vegetation. At large scales, amphibian diversity in floating meadows is mostly determined by stochastic (i.e. random/neutral) processes, whereas at regional scales, climate and deterministic (i.e. niche-based) processes are central drivers. Compared with the turnover of ‘core' species, the turnover of ‘satellite' species increases much faster with distances and is also controlled by a wider range of climatic features. Distance is not a limiting factor for ‘core' species, suggesting that they have a stronger dispersal ability even over large distances. This is probably related to the existence of passive long-distance dispersal of individuals along rivers via vegetation rafts. In this sense, Amazonian rivers can facilitate dispersal, and this effect should be stronger for species associated with riverine habitats such as floating meadows.