Find research datasets worth reusing

Data package from: Mapping Atlantic rainforest degradation and regeneration history with indicator species using convolutional network

This data package contains the very high resolution maps of natural forests as well as map of natural forests dominated by Cecropia hololeuca or Tibouchina pulchra presented in the Figure 8 of the paper "Mapping Atlantic rainforest degradation and regeneration history with indicator species using convolutional network". These maps have be produced with WorldView-2 and WorldView-3 very high resolution images and a deep learning method for image segmentation called U-net (methods and data are fully described in the article). When using this data, please cite the original article <a href="https://doi.org/10.1371/journal.pone.0229448">https://doi.org/10.1371/journal.pone.0229448</a>.

Low-frequency EIS intercept as a diagnostic tool for PEM fuel cells degradation

Several diagnostic tests, such as polarization curves, electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV), were conducted periodically to monitor performance degradation during an accelerated stress test (AST) for catalyst degradation on a single proton exchange membrane (PEM) fuel cell, which involves voltage cycling. From the results of the EIS measurements taken during the AST at three different current densities, catalyst degradation is clearly shown. The lowfrequency intercept (Total R) increased most significantly. The simulation results with an 11-element impedance model show very good agreement with experimental data and consistency with the polarization change curves and CV. The obtained impedance at Total R is purely real, and it can be a useful and perhaps sufficient indicator for catalyst degradation and determination of the cell current state from just one parameter value, which is very promising for the future implementation in the PEM fuel cell control system

Electrochemical low-frequency impedance spectroscopy algorith for diagnostics of PEM fuel cell degradation

In order to estimate fuel-cell degradation status on-line and inexpensively, a diagnostic technique based on relay feedback is developed. The technique can obtain critical parameters within seconds of start-up and is robust to measurement bias. Electrochemical impedance spectroscopy (EIS) is a popular laboratory technique to perform diagnostics on electrochemical systems such as fuel cells, but its application to real-life fuel-cell systems is difficult because of the size and cost of the apparatus. In this study, we present a more detailed equivalent-circuit model for a PEM fuel cell, able to explain the positive reactance shown at low frequencies. Some of these characteristics, measured at several stages during an Accelerated Stress Test (AST), progress gradually with catalyst degradation, providing an effective prognostic variable. In order to measure these characteristics, a relay-based feedback excitation algorithm is developed to estimate the low-frequency intercept in the Nyquist plane of the cell impedance without resorting to a full-fledged EIS. The simulations indicate that the algorithm converges to an estimate within about 5 seconds, and is robust to bias. The algorithm can be run within the standard control system that fuel cells are usually equipped with, with no additional hardware.

Identifying degradation patterns of lithium ion batteries from impedance spectroscopy using machine learning

Dataset accompanying the paper: "Identifying degradation patterns of lithium ion batteries from impedance spectroscopy using machine learning"

opencc-zeroJul 2020View details →

Data for: Synthesis and assessment of schwertmannite/few-layer graphene composite for the degradation of sulfamethazine in heterogeneous Fenton-like reaction

Schwertmannite, an iron oxyhydrosulfate mineral, can catalyze Fenton-like reaction to degrade organic contaminants, but the reduction of Fe(III) to Fe(II) on the surface of schwertmannite is a limiting step for the Fenton-like process. In the present study, the schwertmannite/few-layer graphene composite (sch-FLG) was synthesized to promote the catalytic activity of schwertmannite in Fenton-like reaction. It was found that schwertmannite can be successfully carried by FLG in sch-FLG composite, mainly via the chemical bond of Fe-O-C on the surface of sch-FLG. The sch-FLG exhibited a much higher catalytic activity than schwertmannite or FLG for the degradation of SMT in the heterogeneous Fenton-like reaction, which resulted from that the few-layer graphene can pass electrons efficiently. The degradation efficiency of SMT was around 100% under the reaction conditions of H2O2 200-500 mg L-1, sch-FLG dosage 1-2 g L-1, temperature 28-38 °C, and initial solution pH 1-9. During the repeated uses of sch-FLG in Fenton-like reaction, it maintained a certain catalytic activity for the degradation of SMT and the mineral structure was not changed. In addition, SMT may be finally mineralized in Fenton-like reaction catalyzed by sch-FLG, and the possible degradation pathways were proposed. Therefore, the sch-FLG is an excellent catalyst for SMT degradation in heterogeneous Fenton-like reaction.

opencc-zeroJul 2020View details →

Data from: The fading of fear effects due to coral degradation is modulated by community composition

<ol> <li>An increasing number of coral reefs throughout the world have become degraded as a result of climate change. This degradation has resulted in a significant decline in local biodiversity. Studies have shown that some fishes (non-responders) within these altered habitats are not able to adequately access olfactory cues, specifically chemical alarm cues that are crucial in mediating predation risk.</li> <li>We propose that the inability to access this crucial information is a potential mechanism for increased mortality of these species under natural conditions. However, we posit that the presence of certain key species (responders that are unaffected by degradation) may buffer the handicap of non-responders by providing an alternate source of information.</li> <li>To explore this hypothesis, we investigated if a high ratio of responders to non-responders could mitigate the impact of information loss for the affected species. Using mesocosms, we manipulated the ratio of two damselfish species, Pomacentrus chrysurus (responder) and P. moluccensis (non-responders), to determine if community composition can be predictive of information transfer about predation threats in nearby non-responder individuals.</li> <li>Our results indicate that the magnitude of fear effects seen in P. moluccensis exposed to a predator was proportional to the number of P. chrysurus present and consumed by the predator in the community. This indicates that P. chrysurus became the only functional source of predation-related information for P. moluccensis in degraded habitats.</li> <li>Our study provides evidence that the presence of non-affected species in the community provides a potential mechanism allowing increased resilience by affected species, therefore providing another example of the way biodiversity affects ecological resilience of species in changing ecosystems.</li> </ol>

opencc-by-4.0Aug 2020View details →

Selection of Water-Soluble Chitosan by Microwave-Assisted Degradation and pH Controlled Precipitation

Dataset for "Selection of Water-Soluble Chitosan by Microwave-Assisted Degradation and pH Controlled Precipitation" Polymers (2020) 12, 1274. DOI: 10.3390/polym12061274. Raw data for NMR spectra; raw GPC data; experimental descriptions; metadata file

opencc-zeroAug 2020View details →

Movement rules determine nomadic species' responses to resource supplementation and degradation

1. In environments that vary unpredictably, many animals are nomadic, moving in an irregular pattern that differs from year to year. Exploring the mechanisms of nomadic movement is needed to understand how animals survive in highly variable environments, and to predict behavioral and population responses to environmental change. 2. We developed a network model to identify plausible mechanisms of nomadic animal movement by comparing the performance of multiple movement rules along a continuum from nomadism to residency. Using simulations and analytical results, we explored how different types of habitat modifications (that augment or decrease resource availability) might affect the abundance and movement rates of animals following each of these rules. 3. Movement rules for which departure from patches depended on either resource availability or competition performed almost equally well and better than residency or uninformed movement under most conditions, even though animals using each rule moved at substantially different rates. Habitat modifications that stabilized resources, either by resource supplementation or degradation, eroded the benefits of informed nomadic movements, particularly for movements based on resource availability alone. 4. These results suggest that simple movement rules can explain nomadic animal movements and determine species' responses to environmental change. In particular, landscape stabilization and supplementation might be useful strategies for promoting populations of resident animals, but would be less beneficial for managing highly mobile species, many of which are threatened by habitat disruption and changes in climate.

opencc-zeroNov 2020View details →

Morphoecological characteristics of grasses used to restore degraded semi-arid African rangelands

Progressive loss of productivity and plant diversity has been a major concern for land managers of global arid and semi-arid rangelands. This is often attributed to heavy grazing by large livestock herds and wildlife leading to land degradation threatening millions of livelihoods that rely on rangeland resources. Consequently, combating land degradation has increasingly become important global agenda. Active restoration technologies such as indigenous grass reseeding has been identified as a viable ecological solution for restoring degraded rangeland landscapes and providing forage for sustainable livestock production. Grass species indigenous to African rangelands Cenchrus ciliaris L. (African foxtail grass), Eragrostis superba Peyr. (Maasai love grass), Enteropogon macrostachyus (Hochst. Ex A. Rich.) Monro ex Benth. (Bush rye grass), Chloris roxburghiana Schult. (Horsetail grass) and Chloris gayana Kunth. cv Boma (Rhodes grass) were established in an African semi-arid rangeland landscape under natural conditions to compare their morphoecological characteristics and suitability for ecological restoration. Seed viability, seedling emergence, biomass dry matter yields, plant densities, basal cover, seed production, tiller densities and plant height were determined. Chloris gayana cv Boma and E. superba produced significantly higher dry matter biomass yields and seed production. High biomass and seed production demonstrate their suitability to support livestock production and replenish depleted soil seed banks, respectively. Enteropogon macrostachyus and C. ciliaris displayed significantly higher values for plant densities, tiller densities and basal cover, also used to measure establishment and ecological restoration success. Chloris roxburghiana ranked lowest in all the measured morphoecological characteristics. This could be a strong indicator of ecological site-specific characteristic of C. roxburghiana. Active restoration of degraded African semi-arid rangelands and forage provision for herbivores using indigenous grass reseeding can best be achieved through careful selection of grass species to take advantage on their specific multiple morphoecological characteristics. Furthermore, selection of the grass species to use should primarily be informed by the intended use of the rangeland.

opennotspecifiedNov 2020View details →

FIGURE 2 in A new species of Sphaerotheca Günther, 1859 (Anura: Dicroglossidae) from the degraded urban ecosystems of Bengaluru, Deccan Plateau, India

FIGURE 2. Maximum Likelihood (ML) gene tree for species of Sphaerotheca based on 585 bp of mitochondrial 16S rRNA gene.

opennotspecifiedNov 2020View details →

FIGURE 4 in A new species of Sphaerotheca Günther, 1859 (Anura: Dicroglossidae) from the degraded urban ecosystems of Bengaluru, Deccan Plateau, India

FIGURE 4. Sphaerotheca bengaluru sp. nov. holotype in preservative (A) Dorsal view (B) Ventral view.

opennotspecifiedNov 2020View details →

FIGURE 5 in A new species of Sphaerotheca Günther, 1859 (Anura: Dicroglossidae) from the degraded urban ecosystems of Bengaluru, Deccan Plateau, India

FIGURE 5. Habitat of Sphaerotheca bengaluru sp. nov. from the type locality, a degraded ecosystem of Bengaluru.

opencc-zeroDec 2020View details →

Role of the intestinal microbiome in polyethylene degradation by caterpillar larva of the greater wax moth (Galleria mellonella)

Recently, a few insects, including the caterpillar larva of the greater wax moth Galleria mellonella, have been identified as avid "plastivores". Interestingly, these caterpillars are able to ingest and metabolize polyethylene at unprecedented rates. While it appears that G. mellonella plays an important role in the biodegradation process, the contribution of its intestinal microbiome remains poorly understood and contested. In a series of experiments, we present strong evidence of an intricate relationship between an intact microbiome, low density polyethylene (LDPE) biodegradation, and the production of glycol as a metabolic by-product. First, we biochemically confirmed that G. mellonella larvae consume and metabolize LDPE, as individual caterpillars fed on polyethylene excreted glycol, but those excretions are reduced by antibiotic treatment. Further, while the gut bacterial communities remain relatively stable regardless of diet, we show that during the early phases of feeding on LDPE (24-72 hrs), caterpillars exhibit increased microbial abundance relative to those starved or fed on their natural honeycomb diet. Finally, by isolating and growing gut bacteria with polyethylene as their exclusive carbon source for over one year, we identified microorganisms in the genus Acinetobacter that appear to be involved in this biodegradation process. Taken collectively, our study indicates that during short term exposure, the intestinal microbiome of G. mellonella is intricately associated with polyethylene biodegradation in vivo.

opencc-zeroDec 2015View details →

Data from: Forest degradation and invasive species synergistically impact Mimusops andongensis (Sapotaceae) in Lama Forest Reserve, Benin

Harvesting of Non-Timber Forest Products (NTFPs) can threaten target species, especially those with limited distribution and density. Exploited species also face threats from habitat fragmentation, fire, and invasive species. We assessed the impact of human disturbances and invasive species on the population of a key multipurpose NTFP species, Mimusops andongensis, in Lama Forest reserve (Benin). The densities of adult trees and regenerative stems decreased with increasing degradation. Mimusops andongensis contributed less to total tree density with increasing human disturbance. There were significantly fewer M. andongensis recruits with increasing cover of invasive Chromolaena odorata. Smaller diameter individuals predominated in non-degraded and moderately degraded sites while in degraded sites, the structure showed a negative exponential trend with the density of small diameter individuals being less than two trees/ha. Larger individuals were also rare in degraded sites. The low density of both mature trees and seedlings in degraded sites may undermine the long-term viability of M. andongensis, despite existing protection against NTFP harvesting and other anthropogenic pressures. Management should emphasize facilitating recruitment subsidies and limiting the presence of C. odorata.

opencc-zeroDec 2013View details →

Data from: Balancing sample accumulation and DNA degradation rates to optimize noninvasive genetic sampling of sympatric carnivores

Noninvasive genetic sampling, or noninvasive DNA sampling (NDS), can be an effective monitoring approach for elusive, wide-ranging species at low densities. However, few studies have attempted to maximize sampling efficiency. We present a model for combining sample accumulation and DNA degradation to identify the most efficient (i.e. minimal cost per successful sample) NDS temporal design for capture–recapture analyses. We use scat accumulation and faecal DNA degradation rates for two sympatric carnivores, kit fox (Vulpes macrotis) and coyote (Canis latrans) across two seasons (summer and winter) in Utah, USA, to demonstrate implementation of this approach. We estimated scat accumulation rates by clearing and surveying transects for scats. We evaluated mitochondrial (mtDNA) and nuclear (nDNA) DNA amplification success for faecal DNA samples under natural field conditions for 20 fresh scats/species/season from <1–112 days. Mean accumulation rates were nearly three times greater for coyotes (0.076 scats/km/day) than foxes (0.029 scats/km/day) across seasons. Across species and seasons, mtDNA amplification success was ≥95% through day 21. Fox nDNA amplification success was ≥70% through day 21 across seasons. Coyote nDNA success was ≥70% through day 21 in winter, but declined to <50% by day 7 in summer. We identified a common temporal sampling frame of approximately 14 days that allowed species to be monitored simultaneously, further reducing time, survey effort and costs. Our results suggest that when conducting repeated surveys for capture–recapture analyses, overall cost-efficiency for NDS may be improved with a temporal design that balances field and laboratory costs along with deposition and degradation rates.

opencc-zeroDec 2012View details →

Data from: The hindgut-lumen prokaryotic microbiota of the lignocellulose-degrading termite Reticulitermes flavipes and its responses to dietary lignocellulose composition

Reticulitermes flavipes (Isoptera: Rhinotermitidae) is a highly eusocial insect that thrives on recalcitrant lignocellulosic diets through nutritional symbioses with gut-dwelling prokaryotes and eukaryotes. In the R. flavipes hindgut, there are up to 12 eukaryotic protozoan symbionts; the number of prokaryotic symbionts has been estimated in the hundreds. Despite its biological relevance, this diverse community, to date, has been investigated only by culture- and cloning-dependent methods. Moreover, it is unclear how termite gut microbiomes respond to diet changes and what roles they play in lignocellulose digestion. This study utilized high-throughput 454 pyrosequencing of 16S V5-V6 amplicons to sample the hindgut lumen prokaryotic microbiota of R. flavipes and to examine compositional changes in response to lignin-rich and lignin-poor cellulose diets after a 7-day feeding period. Of the ~475 000 high-quality reads that were obtained, 99.9% were annotated as bacteria and 0.11% as archaea. Major bacterial phyla included Spirochaetes (24.9%), Elusimicrobia (19.8%), Firmicutes (17.8%), Bacteroidetes (14.1%), Proteobacteria (11.4%), Fibrobacteres (5.8%), Verrucomicrobia (2.0%), Actinobacteria (1.4%) and Tenericutes (1.3%). The R. flavipes hindgut lumen prokaryotic microbiota was found to contain over 4761 species-level phylotypes. However, diet-dependent shifts were not statistically significant or uniform across colonies, suggesting significant environmental and/or host genetic impacts on colony-level microbiome composition. These results provide insights into termite gut microbiome diversity and suggest that (i) the prokaryotic gut microbiota is much more complex than previously estimated, and (ii) environment, founding reproductive pair effects and/or host genetics influence microbiome composition.

opencc-zeroDec 2016View details →

Data from: Effects of small-scale, shading-induced seagrass loss on blue carbon storage: Implications for management of degraded seagrass ecosystems

1. Seagrass meadows are important global 'blue carbon' sinks. Despite a 30% loss of seagrasses globally during the last century, there is limited empirical research investigating the effects of disturbance and loss of seagrass on blue carbon stocks. 2. In this study, we hypothesised that seagrass loss would reduce blue carbon stocks. Using shading cloth, we simulated small-scale die-offs of two subtropical seagrass species, Halodule wrightii and Thalassia testudinum, in a dynamic northern Gulf of Mexico lagoon. The change in quantity and quality of sediment organic matter and organic carbon were compared among kill, control and bare plots before the kill treatment, shortly after the kill treatment and 11 months after the kill treatment. 210 Pb age dating was performed on bare and Thalassia plots at 11 months to evaluate the impact of sediment erosion in the absence of vegetation. 3. The small-scale die-off led to a 50-65% organic matter (OM) loss in the sediment in the top 8 cm of Halodule plots. Thalassia plots lost significant portions OM (50%) and organic carbon (C; 21-47%) in only the top 1 cm of sediment. The 210 Pb profiles indicated Thalassia die-off reduced the C sequestration rate by 10%, in addition to a loss of ~1 years' worth of C stocks (~22 g m-2<). Furthermore, analyses on O Morg quality indicated a loss of labile OM/C and enhanced remineralisation by microbes. 4. Synthesis and applications: This study provides empirical evidence that small-scale shading-induced seagrass die-offs can reduce seagrass carbon sequestration capacity and trigger losses of blue carbon stocks. While the losses recorded here are modest, these losses in blue carbon storage capacity are notable due to the proximity of shading structures (for example, boat docks) to seagrass habitats. Thus, policies to avoid or protect seagrass habitats from common small-scale, shading disturbances are important for optimising both carbon sequestration capacity and coastline development and management.17-Nov-2017

opencc-zeroDec 2014View details →

Data from: Variation in the impact of non-native seaweeds along gradients of habitat degradation: a meta-analysis and an experimental test

Biological invasions are acknowledged among the main drivers of global changes in biodiversity. Despite compelling evidence of species interactions being strongly regulated by environmental conditions, there is a dearth of studies investigating how the effects of non-native species vary among areas exposed to different anthropogenic pressures. Focusing on marine macroalgae, we performed a meta-analysis to test whether and how the direction and magnitude of their effects on resident communities and species varies in relation to cumulative anthropogenic impact levels. The relationship between human impact levels and non-native species impact intensity emerged only for a reduced subset of the response variables examined. Yet, there was a trend for the effects of non-native species on community biomass and abundance and on species abundance to become less negative at heavily impacted sites. By contrast, the magnitude of negative effects of seaweed on community evenness tended to increase with human impact levels. The hypothesis of decreasing severity of invader' impacts along a gradient of habitat degradation was also tested experimentally at a regional scale by comparing the effects of the removal of non-native alga, Caulerpa cylindracea, on resident assemblages among rocky reefs exposed to different anthropogenic pressures. Assemblages at urban and pristine site did not differ when invaded, but did so when C. cylindracea was removed. Our results suggest that, despite the generally weak relationship between human impacts levels and non-native species impacts, more negative impacts can be expected in less stressful environments (i.e. less degraded or pristine sites), where competitive interactions are presumably the driving force structuring resident communities. Implementing strategies for controlling the establishment of non-native seaweeds should be, thus, considered a priority for preserving biodiversity in relatively pristine areas. On the other hand, control of invaders at degraded sites could be warranted to lessen their role as propagule sources.