Intermediate Cover Research Articles

Natural coastal dunes on Wadden Sea islands as a refuge for an endangered wader species

Europe holds globally important populations of breeding waders. However, most of the species are in steep decline, including the Eurasian Curlew (Numenius arquata). Here, we studied the breeding-territory and nest-site preferences of a Curlew subpopulation that has, in contrast to the overall trend, been increasing, on the East Frisian Islands (Wadden Sea National Park of Lower Saxony, N Germany). The islands are mostly free from ground predators and intensive agriculture and thus offer the opportunity to examine habitat preferences in largely undisturbed habitats. Our study revealed that Curlews preferred breeding in habitat mosaics dominated by high marshes and dune grasslands, far from areas with human disturbance. For nest-building, heterogeneous microhabitats with intermediate vegetation cover and height and some bare ground were preferred. This reflects a trade-off between (i) sufficient shelter for nests and fledglings, (ii) early recognition of predators and (iii) readily available and accessible invertebrate prey. Such heterogeneous habitats, without mammalian predators, are largely missing in the intensively used agricultural landscapes of the European mainland. Consequently, Curlew populations on the mainland are mostly declining. In contrast, those on the East-Frisian Islands are stable and, therefore, of prime importance for the protection of the species. Thus, the study highlights the importance of isolated islands providing natural habitats like coastal dunes, which are free from ground predators and extensive human disturbance for the long-term survival of Curlew populations. Based on the results of this study we make suggestions to improve future conservation measures for degraded habitats to boost curlew populations.

New deep data hiding and extraction algorithm using multi-channel with multi-level to improve data security and payload capacity.

The main challenge in steganography algorithms is balancing between the size of the secret message (SM) that is embedded in the cover image (CI) and the quality of the stego-image (SI). This manuscript proposes a new steganography algorithm to hide a large amount of secret messages in cover images with a high degree of non-perception in the resulting images. The proposed algorithm applied a multi-channel deep data hiding and extraction algorithm (MCDHEA) based on a modified multi-level steganography (MLS) approach. This approach used a new modification of the least significant bits (NMLSB) to make it hard to extract a secret message from attackers. The secret message was distributed among n-blocks; each block was hidden into a sub-channel that included multi-level hiding and flows into the main channel. Different grayscale images were used through the levels of each sub-channel and using the color image in the last level of the main channel. The image size of the multi-level was expanded from one level to the next level, and at each level, lossless image compression using the Huffman coding algorithm was applied to enable the size of the data hiding at the next level. In addition, the encryption of secret messages and intermediate cover images based on the XOR encryption algorithm is applied before the hiding process. Finally, the number of bits to be replaced at each level for both sub and main channels was four bits per byte except at the last level of the main channel based on a new approach using a non-uniform number of bits replacements. This algorithm's performance was evaluated using various measures. The results show that the proposed technique is effective and better than the previous works concerning imperceptibility and robustness. Furthermore, the results show that the maximum peak signal-to-noise ratio (PSNR) of 61.2 dB for the payload of 18,750 bytes, the maximum video information fidelity (VIF) of 0.95 for the payload of 19,660 bytes, and the maximum structural similarity index measure (SSIM) of 0.999 for the payload of 294,912 bytes.

Effects of landscape composition on hoverflies (Diptera: Syrphidae) in mass-flowering crop fields within forest-dominated landscapes

Agricultural intensification has led to structurally simplified landscapes with reduced and fragmented resources for farmland insects. However, studies on the effects of landscape composition on farmland insects have mainly been performed in areas dominated by open arable land and semi-natural grasslands, while studies from forest-dominated landscapes are scarce. This research examined the effects of landscape composition on hoverfly species richness and abundance in arable land in boreal forest-dominated landscapes. Hoverflies were sampled in 22 mass-flowering caraway (Carum carvi) fields in Central Finland using pan traps. The effects of landscape composition on species richness and abundance were examined for all hoverflies, and for species groups with different adult habitat preferences. Landscape composition was measured as proportions of land cover classes within two different radii. Species richness and abundances of all hoverflies, forest species and open-habitat species increased with decreasing arable land cover and/or increasing forest cover within a 500 m radius (the two land cover classes strongly negatively correlated). Wetland species were most abundant in landscapes with an intermediate cover of arable land and forest, and most species-rich in landscapes with intermediate (10%) water cover. The species richness and abundance of mixed-habitat species increased with increasing cover of transitional woodland.Implications for insect conservationOur results show that most hoverfies in arable land benefit from increasing surrounding forest cover even in relatively heterogeneous, forest-dominated landscapes. Preserving or increasing the area of forests and other non-arable habitats is needed to safeguard a diversity of resources for hoverflies, and associated ecosystem services in farmland.

Odor emission rate of a municipal solid waste sanitary landfill during different operation stages before final closure

This study investigated the odor emission rate from different areas of a municipal solid waste landfill. The surface odor emission rate (SOER) of eight odorous compound groups were determined by flux chamber method. The SOER of working face, seams of daily cover, membrane surface of daily cover, seams of temporary cover, membrane surface of temporary cover, seams of intermediate cover, membrane surface of intermediate cover were 138.34, 49.83, 13.56, 90.35, 14.48, 4.05, and 8.14 μg/(m2·s), respectively. Therefore, odor emission hotspots were at seams of daily and temporary cover areas. Converting the odor emissions at emission hotspots to the entire membrane cover surface, the average SOER of working face, daily cover area, temporary cover area and intermediate cover area were 138.34, 17.95, 22.43, and 6.24 μg/(m2·s), respectively. Combined with the size of each landfill area, the total odor emissions of the four above areas of a landfill zone were 830, 108, 1346, and 5175 mg/s, respectively, suggesting the necessity to control the odor emission of membrane cover stages especially for large-scale landfills. In terms of odor components, alcohols (38.7 %), sulfur compounds (22.9 %) and aldehydes (15.7 %) were major odorous groups.

Habitat thresholds for successful predation under landscape change

ContextHabitat loss and alteration affect wildlife populations worldwide. Bush encroachment alters landscapes and threatens arid and semi-arid grasslands, but its effects on predator–prey relationships and carnivore community ecology are not well understood. Predation strategies of large predators, for example high-speed pursuits versus ambush from short distances, are likely to be affected differently by bush encroachment.ObjectivesWe assessed how bush encroachment affects overall predation success of cheetahs (Acinonyx jubatus) and leopards (Panthera pardus) in a savanna landscape under variable fractional woody cover (FWC). We tested if predation success remained relatively unchanged for leopards across a gradient of FWC, and whether cheetah predation was most successful at low to intermediate cover and varied seasonally.MethodsBelly scores of predators were measured from camera-trap images collected over 7 years in north-central Namibia and used to index predation success. We derived predicted belly score probabilities as a function of FWC, which was measured using a Synthetic Aperture Radar (SAR)-derived satellite data layer.ResultsPredicted leopard predation success was highest at 0.27–0.34 FWC in the dry season, potentially due to lower prey density in highly covered areas and decreased prey catchability in low cover. Predicted cheetah predation success was highest at 0.24–0.28 FWC in the wet season, potentially due to increased landscape openness, high availability of habitat margins for visualising and stalking prey, and decreased kleptoparasitism by leopards. These results highlight optimal habitat cover thresholds that favour lower FWC for cheetah than for leopard.ConclusionsThe findings indicate that landscape heterogeneity is important for predation success of cheetahs and leopards, suggesting that habitat management should focus on bush control efforts to maintain intermediate levels of bush cover.

Integrating herbivore assemblages and woody plant cover in an African savanna to reveal how herbivores respond to ecosystem management.

African savannas are experiencing anthropogenically-induced stressors that are accelerating the increase of woody vegetation cover. To combat this, land managers frequently implement large-scale clearing of trees, which can have a cascading influence on mammalian herbivores. Studies rarely focus on how differences in woody cover influence the herbivore assemblage, making it difficult to assess how aggressive measures, or the lack of management, to counteract increasing woody cover affect the local composition and biodiversity of herbivores. We address this knowledge gap by applying a model-based clustering approach to field observations from MalaMala Game Reserve, South Africa to identify multiple herbivore–vegetation ‘configurations,’ defined as unique sets of herbivore assemblages (i.e., groups of herbivores) associated with differing woody plant covers. Our approach delineated how tree-clearing influences the distribution and abundance of the herbivore community in relation to surrounding savanna areas, which represent a natural mosaic of varying woody cover. Regardless of season, both intensively managed areas cleared of trees and unmanaged areas with high tree cover contained configurations that had depauperate assemblages of herbivores (low species richness, low abundance). By contrast, habitats with intermediate cover of woody vegetation had much higher richness and abundance. These results have substantial implications for managing African savannas in a rapidly changing climate.

Canopy Cover and Canopy Heterogeneity Drive Plant Alpha Diversity But Not Beta Diversity in a Midwest Oak Savanna

Midwest oak savannas contain some of the highest plant diversity in the United States and are among the rarest terrestrial ecosystems globally. Consequently, understanding diversity patterns within these ecosystems is important for setting management and restoration goals. This study aimed to understand the role of canopy cover and heterogeneity in canopy cover in influencing plant alpha and beta diversity within oak savanna ecosystems. This study took place in the black oak savannas of the Indiana Dunes along the southern shores of Lake Michigan in NW Indiana, USA. We sampled twenty-nine 1000 m2 plots with gradients in canopy cover and canopy heterogeneity across the Indiana Dunes to examine the influence of canopy cover and canopy heterogeneity on plant diversity. Woody plant alpha diversity was highest in areas with a high canopy cover (>75%). C3 graminoids, C4 graminoids, and sedge alpha diversity were highest in low canopy cover areas (<25%). Forb and legume alpha diversity were highest with low to intermediate canopy cover (25–50% and 20–35%). Overall, plant alpha diversity was highest at intermediate canopy cover. High canopy heterogeneity was associated with high alpha diversity. There was no relationship between canopy cover or canopy heterogeneity with beta diversity. However, beta diversity was exceptionally high within all sites. An average canopy cover of 25–50% is the optimal cover for promoting high plant diversity across many functional groups. Still, low and high canopy cover sites are also important for maximizing diversity of some functional groups. Therefore, we recommend managing oak savannas for 25–50% canopy cover to maximize diversity, but where opportunities exist in large remnants of oak savanna, maintaining some areas with few trees and other areas with closed canopies can maximize diversity on a landscape scale.

Study of the Effects of Current Imbalance in a Multiphase Buck Converter for Electric Vehicles

The excessive use of fossil fuels has caused great concern due to modern environmental problems, particularly air pollution. The above situation demands that different areas of research aim at a sustainable movement to reduce CO2 emissions caused by non-renewable organic fuels. A solution to this problem is the use of Electric Vehicles (EV) for mass transportation of people. However, these systems require high-power DC/DC converters capable of handling high current levels and should feature high efficiencies to charge their batteries. For this application, a single-stage converter is not viable for these applications due to the high current stress in a switch, the low power density, and its low efficiency due to higher switching losses. One solution to this problem is Multiphase Converters, which offer high efficiency, high power density, and low current ripple on the battery side. However, these characteristics are affected by the current imbalance in the phases. This paper is focused on the study of the effects of the current imbalance in a Multiphase Buck Converter, used as an intermediate cover between a power supply and the battery of an EV. Analyzing the efficiency and thermal stress parameters in different scenarios of current balance and current imbalance in each phase.

Clinical application of three-dimensional printed preformed titanium mesh combined with free latissimus dorsi muscle flap in the treatment of squamous cell carcinoma with skull defect in the vertex

Objective: To explore the clinical effects of three-dimensional printed preformed titanium mesh combined with latissimus dorsi muscle flap free transplantation in the treatment of wounds with skull defect after radical surgery of squamous cell carcinoma in the vertex. Methods: A retrospective observational study was conducted. From January 2010 to December 2019, 5 patients with squamous cell carcinoma in the vertex accompanied with skull invasion who met the inclusion criteria were admitted to the Department of Burns and Plastic Surgery of the Second Affiliated Hospital of Air Force Medical University, including four males and one female, aged 50 to 65 years. The original lesion areas ranged from 5 cm×4 cm to 15 cm×8 cm. The titanium mesh was prefabricated via three-dimensional technic based on the result the scope of skull resection predicted with computerized tomography three-dimensional reconstruction before surgery. During the first stage, the soft tissue defect area of scalp (8 cm×7 cm to 18 cm×11 cm) after tumor enlargement resection was repaired with the preformed titanium mesh, and the titanium mesh was covered with latissimus dorsi muscle flap, with area of 10 cm×9 cm to 20 cm×13 cm. The thoracodorsal artery/vein was anastomosed with the superficial temporal artery/vein on one side. The muscle ends in the donor site were sutured together or performed with transfixion, and then the skin on the back were covered back to the donor site. On the 10th day after the first-stage surgery, the second-stage surgery was performed. The thin intermediate thickness skin graft was taken from the anterolateral thigh to cover the latissimus dorsi muscle flap. The duration and intraoperative blood loss of first-stage surgery were recorded. The postoperative muscle flap survival after the first-stage surgery and skin graft survival after the second-stage surgery was observed. The occurrence of complications, head appearance, and recurrence of tumor were followed up. Results: The average first-stage surgery duration of patients was 12.1 h, and the intraoperative blood loss was not more than 1 200 mL. The muscle flaps in the first-stage surgery and the skin grafts in the second-stage surgery all survived well. During the follow-up of 6-18 months, no complications such as exposure of titanium mesh or infection occurred, with good shape in the recipient sites in the vertex, and no recurrence of tumor. Conclusions: Three-dimensional printed preformed titanium mesh combined with latissimus dorsi muscle flap free transplantation and intermediate thickness skin graft cover is an effective and reliable method for repairing the wound with skull defect after extended resection of squamous cell carcinoma in the vertex. This method can cover the wound effectively as well as promote both recipient and donor sites to obtain good function and appearance.

Remotely sensed variables explain microhabitat selection and reveal buffering behaviours against warming in a climate‐sensitive bird species

AbstractFine‐scale habitat selection modelling can allow a mechanistic understanding of habitat selection processes, enabling better assessments of the effects of climate and habitat changes on biodiversity. Remotely sensed data provide an ever‐increasing amount of environmental and climatic variables at high spatio‐temporal resolutions, and a unique opportunity to produce fine‐scale habitat models particularly useful in challenging environments, such as high‐elevation areas. Working at a 10‐m spatial resolution, we assessed the value of remotely sensed data for investigating foraging habitat selection (in relation to topography, microclimate, land cover) in nestling‐rearing white‐winged snowfinch (Montifringilla nivalis), a high‐elevation species highly sensitive to climate change. Adult snowfinches foraged at locations with intermediate vegetation cover and higher habitat heterogeneity, also avoiding extremely warm or extremely cold microclimates. Temperature interacted with other environmental drivers in defining habitat selection, highlighting trade‐offs between habitat profitability and thermoregulation: snowfinches likely adopted mechanisms of behavioural buffering against physiologically stressful conditions by selecting for cooler, shaded and more snowy foraging grounds at higher temperatures. Our results matched those from previous studies based on accurate field measurements, confirming the species' reliance on climate‐sensitive microhabitats (snow patches and low‐sward grassland, in heterogeneous patches) and the usefulness of satellite‐derived fine‐scale modelling. Habitat suitability models built on remotely sensed predictors can provide a cost‐effective method for periodic monitoring of species' habitats both at fine grain and over large extents. Fine‐scale models also enhance our understanding of the actual drivers of (micro)habitat selection and of possible buffering behaviours against warming, allowing more accurate and robust distribution models, finer predictions of potential future changes and carefully targeted conservation strategies and habitat management.

Changes in Container-Breeding Mosquito Diversity and Abundance Along an Urbanization Gradient are Associated With Dominance of Arboviral Vectors.

Environmental conditions associated with urbanization are likely to influence the composition and abundance of mosquito (Diptera, Culicidae) assemblages through effects on juvenile stages, with important consequences for human disease risk. We present six years (2011-2016) of weekly juvenile mosquito data from distributed standardized ovitraps and evaluate how variation in impervious cover and temperature affect the composition and abundance of container-breeding mosquito species in Maryland, USA. Species richness and evenness were lowest at sites with high impervious cover (>60% in 100-m buffer). However, peak diversity was recorded at sites with intermediate impervious cover (28-35%). Four species were observed at all sites, including two recent invasives (Aedes albopictus Skuse, Ae. japonicus Theobald), an established resident (Culex pipiens L), and one native (Cx. restuans Theobald). All four are viral vectors in zoonotic or human transmission cycles. Temperature was a positive predictor of weekly larval abundance during the growing season for each species, as well as a positive predictor of rapid pupal development. Despite being observed at all sites, each species responded differently to impervious cover. Abundance of Ae. albopictus larvae was positively associated with impervious cover, emphasizing that this medically-important vector not only persists in the warmer, impervious urban landscape but is positively associated with it. Positive temperature effects in our models of larval abundance and pupae occurrence in container habitats suggest that these four vector species are likely to continue to be present and abundant in temperate cities under future temperature scenarios.

N-mixture models provide informative crocodile (Crocodylus moreletii) abundance estimates in dynamic environments.

Estimates of animal abundance provide essential information for population ecological studies. However, the recording of individuals in the field can be challenging, and accurate estimates require analytical techniques which account for imperfect detection. Here, we quantify local abundances and overall population size of Morelet’s crocodiles (Crocodylus moreletii) in the region of Calakmul (Campeche, Mexico), comparing traditional approaches for crocodylians (Minimum Population Size—MPS; King’s Visible Fraction Method—VFM) with binomial N-mixture models based on Poisson, zero-inflated Poisson (ZIP) and negative binomial (NB) distributions. A total of 191 nocturnal spotlight surveys were conducted across 40 representative locations (hydrologically highly dynamic aquatic sites locally known as aguadas) over a period of 3 years (2017–2019). Local abundance estimates revealed a median of 1 both through MPS (min–max: 0–89; first and third quartiles, Q1–Q3: 0–7) and VFM (0–112; Q1–Q3: 0–9) non-hatchling C. moreletii for each aguada, respectively. The ZIP based N-mixture approach shown overall superior confidence over Poisson and NB, and revealed a median of 6 ± 3 individuals (min = 0; max = 120 ± 18; Q1 = 0; Q3 = 18 ± 4) jointly with higher detectabilities in drying aguadas with low and intermediate vegetation cover. Extrapolating these inferences across all waterbodies in the study area yielded an estimated ~10,000 (7,000–11,000) C. moreletii present, highlighting Calakmul as an important region for this species. Because covariates enable insights into population responses to local environmental conditions, N-mixture models applied to spotlight count data result in particularly insightful estimates of crocodylian detection and abundance.

The distribution and impact of an invasive plant species (Senecio inaequidens) on a dune building engineer (Calamagrostis arenaria)

Disturbance is thought to enhance the probability of invasive species establishment, a prerequisite for naturalisation. Coastal dunes are characterised by disturbance in the form of sand dynamics. We studied the effect of this disturbance on the establishment and spread of an invasive plant species (Senecio inaequidens) in European coastal dunes. Local sand dynamics dictate the spatial configuration of marram grass (Calamagrostis arenaria). Therefore, marram grass configuration was used as a reliable proxy for disturbance. Since marram grass plays a crucial role in natural dune formation, we evaluated the possible effects S. inaequidens could have on this process, if it is able to naturalise in European coastal dunes. We expected the highest probability of S. inaequidens establishment at intermediate marram grass cover because too low cover would increase sand burial, whereas high cover would increase competition. However, our results indicate that S. inaequidens is quite capable of handling higher levels of sand burial. Thus, the probability of S. inaequidens establishment was high under low marram cover but slightly lowered when marram cover was high, hinting at the importance of competition. We expected a negative impact of Senecio-altered soils on marram grass growth mediated by soil biota. However, marram grass grew better in sand gathered underneath Senecio plants due to abiotic soil modifications. This enhanced growth may be caused by Senecio leaf litter elevating nutrient concentrations in an otherwise nutrient-poor substrate. If such increased plant growth is a general phenomenon, further expansion of S. inaequidens could accelerate natural succession in European coastal dunes.

Hydroclimatic adaptation critical to the resilience of tropical forests.

Forest and savanna ecosystems naturally exist as alternative stable states. The maximum capacity of these ecosystems to absorb perturbations without transitioning to the other alternative stable state is referred to as ‘resilience’. Previous studies have determined the resilience of terrestrial ecosystems to hydroclimatic changes predominantly based on space‐for‐time substitution. This substitution assumes that the contemporary spatial frequency distribution of ecosystems’ tree cover structure holds across time. However, this assumption is problematic since ecosystem adaptation over time is ignored. Here we empirically study tropical forests’ stability and hydroclimatic adaptation dynamics by examining remotely sensed tree cover change (ΔTC; aboveground ecosystem structural change) and root zone storage capacity (S r; buffer capacity towards water‐stress) over the last two decades. We find that ecosystems at high (>75%) and low (<10%) tree cover adapt by instigating considerable subsoil investment, and therefore experience limited ΔTC—signifying stability. In contrast, unstable ecosystems at intermediate (30%–60%) tree cover are unable to exploit the same level of adaptation as stable ecosystems, thus showing considerable ΔTC. Ignoring this adaptive mechanism can underestimate the resilience of the forest ecosystems, which we find is largely underestimated in the case of the Congo rainforests. The results from this study emphasise the importance of the ecosystem's temporal dynamics and adaptation in inferring and assessing the risk of forest‐savannah transitions under rapid hydroclimatic change.

Regional differences in influence of intermediate cover permeability on perched leachate in landfill

Intermediate cover may act as impervious layers in landfill and form perched leachates, which have adverse effects on the safe operation of landfill. The formation rules of perched leachate mound in different climate regions are not the same and still unclear. To solve this problem, a finite difference method that took account of climate boundaries was conducted. Four typical cities' climate data standing for Chinese climate and 4 permeability parameters of intermediate cover were used in the simulation. The results showed that key to the formation of perched leachate is that the infiltration rate of the leachate is greater than the ks of the intermediate cover. Under arid climate conditions, the infiltrates of the leachate are generally lower than the infiltration capacity of the intermediate cover, and it is not easy to form a perched leachate mound. In humid regions, when the ks of the intermediate cover is lower than 10−5 cm/s, perched leachate forms easily in rainy seasons. The result can be useful to determine the permeability parameters of intermediate cover, especially in humid climate.

Functional responses of mangrove fauna to forest degradation

Structural degradation of mangroves through the partial removal of trees is globally pervasive and likely to affect ecological functioning, including habitat provisioning for biodiversity. Biodiversity responses will depend on the severity of degradation, yet few studies have contraste and quantified several degradation states. Addressing this knowledge gap, we sampled faunal diversity across a range of mangrove forests in southern Kenya. Canopy cover was the strongest predictor of faunal responses among forest structural variables. Faunal abundance, species richness and biodiversity all decreased with reduction in canopy cover, and taxonomic and functional composition changed. The trophic diversity of crabs peaked at intermediate canopy cover, with degraded habitats having more generalist species and fewer specialists. Functional redundancy was unaffected by canopy thinning. The decline in functional diversity and richness of brachyuran crabs with canopy cover implies that resource-use efficiency weakens with increasing degradation. Our results are indicative of significant alterations to forest functioning with degradation, because epibenthic fauna are important regulators of mangrove ecosystem processes, including nutrient cycling and carbon.

Using citizen science to understand and map habitat suitability for a synurbic mammal in an urban landscape: the hedgehog Erinaceus europaeus

Abstract Urban environments are important for west European hedgehogs Erinaceus europaeus. The species has been recorded in 73% of large urban areas throughout its geographic range. However, the environmental relationships determining hedgehog distribution within these landscapes are not well understood. Taking a city‐wide perspective, this study identifies hedgehogs’ habitat relationships with urban environmental characteristics and predicts habitat suitability in a major urban centre, Greater London, UK. We use a collated citizen science dataset of 3012 hedgehog occurrence records from Greater London, and pseudoabsences inferred from other mammal taxa, to construct a multiscale generalised linear model identifying the influence of 10 variables representing urban greenspace, built infrastructure, and the presence of the European badger Meles meles (as a predator or competitor) on hedgehog distribution. We find a positive association of hedgehog presence with availability of gardens, parks, allotments, percentage of terraced housing, traffic, and intermediate impervious cover (roads and buildings, peaking at 31%). High impervious cover, woodland, water, human densities (above 2262 people km−2), and badger presence were negatively related to hedgehog presence. Predicted habitat suitability was high across much of Greater London but declined towards the centre and in some locations around the outskirts of the study region. Our results emphasise the importance of public and private greenspaces for urban hedgehogs, and suggest that loss of garden, park, and allotment habitats and disturbance associated with high human densities may restrict hedgehog distribution. Despite the inherent complexity of urban environments, this study shows that citizen science is useful for developing an understanding of large‐scale species–habitat relationships in diverse urban landscapes.

Molar-incisor hypomineralisation: narrative review on etiology, epidemiology, diagnostics and treatment decision.

Molar-incisor hypomineralisation (MIH) is clinically defined as demarcated structural enamel defects affecting at least one first permanent molar with or without the involvement of incisors. It is foremost a qualitative developmental defect of systemic origin. The prevalence for MIH is estimated at 12.9% with significant differences between countries. Its etiology and pathogenesis are still not completely understood. Several environmental and medical causes have been suggested to alter enamel maturation. The hypomineralised enamel may collapse shortly after eruption and as a consequence caries lesions seem more likely to develop. Besides cavitation, hypersensitivity and/or pain are the hallmarks of clinical symptoms. Both are associated with increased dental anxiety and fear of children suffering from MIH. Consequently, patients' care and management are challenging and necessitates a large range of non-, micro- and invasive strategies. MIH might be mixed up with three different other types of developmental defects in the enamel: fluorosis, enamel hypoplasia, and amelogenesis imperfecta. Careful diagnostic differentiation should be made before starting any dental treatment. A recent published classification system links the severity of the lesion to a treatment need index. This index is based on four values regarding two key symptoms: hypersensitivity and post-eruptiv enamel breakdown (PEB). Without PEB sealing is strongly recommended in order to prevent caries. For hypersensitive teeth as well as those with PEB use of glass ionomer cement as an intermediate cover, but mainly composite resins are materials of choice. For improvement of aesthetically compromised MIH-incisors, the resin infiltration technique has been proposed.

The invasive herb Lupinus polyphyllus can reduce plant species richness independently of local invasion age

The ecological impacts of invasive species may change or accumulate with time since local invasion, potentially inducing further changes in communities and the abiotic environment. Yet, time since invasion is rarely considered when investigating the ecological impacts of invasive non-native species. To examine the effect of time since invasion on the ecological impacts of Lupinus polyphyllus, a perennial nitrogen-fixing herb, we surveyed vascular plant communities in the presence and absence of L. polyphyllus in young, intermediate, and old semi-natural grassland sites (ca. 5, 10, 15 years representing both time since lupine invasion and plant community age). We analyzed vascular plant community composition, vascular plant species richness, and the cover of various ecological plant groups and L. polyphyllus. In contrast to our hypotheses, we found no change in the mean cover of L. polyphyllus (about 35%) with time since local invasion, and an ordination did not suggest marked changes in plant community composition. L. polyphyllus was associated with lower species richness in invaded plant communities but this effect did not change with time since invasion. Invaded plant communities were also associated with lower occurrence of generalist, oligotrophic (low-nutrient-adapted) and copiotrophic (nutrient-demanding) species but no temporal dynamics were detected. We conclude that even the intermediate cover of L. polyphyllus can reduce plant species richness, but the ecological impact caused by this invader might not dramatically change or accumulate with time since invasion.

Performance of food-waste compost biocovers in mitigating methane emission from landfills

This paper presents the results of an experimental programme that was employed to investigate the performance of biocovers made of food-waste compost in mitigating methane emissions from municipal solid waste landfills in a semi-dry environment. Five experimental columns containing biocover materials made of compost mixed with landfill intermediate cover soil at different compost/soil mixture ratios were exposed to methane inflow under ambient temperature over a period of 3 months. Methane removal efficiencies were determined based on methane content measurements using gas chromatography, bacterial count and scanning electron microscopy performed on biocover samples over time. The biocover materials made of 70% compost and 30% soil demonstrated significantly higher methane removal efficiencies compared with other mixtures, measuring an emission reduction of about 63%. The compost type and composition were also found to affect the methane removal efficiency of biocover materials. These findings can be used for selection of compost type and compost/soil mixture ratio as biocover materials.