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795 results for “fluctuations”
Mechanical energy fluctuation in lower limbs during walking in participants with and without total hip replacement
<p>Mechanical energy fluctuation of the segments in the lower limbs during walking has not been fully investigated. It was hypothesised that the segments of the lower limbs may work as a pendulum, i.e., the kinetic and potential energies exchanged out of phase. This study aimed to investigate energy changes and recovery during gait in hip replacement patients. The gait data for 12 participants with total hip replacement and 12 age-matched controls were compared. The kinetic, potential, and rotative energies for the whole lower limb and thigh, calf, and foot, were calculated. The effectiveness of a pendulum effect was analysed. Gait parameters, e.g., walking speeds, cadence, and stride length were calculated. The results showed that the thigh had significant effectiveness as a pendulum during gait with an energy recovery coefficient of approximately 40% while the calf and foot were less like a pendulum during gait. In comparison, energy recoveries of the lower limbs in the two groups were not significantly different. If the centre of the pelvis was considered as approximate to the centre of mass, however, the control group had a higher energy recovery than the total hip replacement group by roughly 10%. This study concluded that the mechanical energy recovery mechanism in the lower limbs during walking exists for two groups.</p>
Net effect of environmental fluctuations in multiple global-change drivers across the tree of life
<p>This dataset contains the raw data presented in the article and supplementary material by M. J. Cabrerizo and E. Marañón entitled: "<strong>Net effect of environmental fluctuations in multiple global-change drivers across the tree of life"</strong></p>
Brain waves would include equipotential fluctuations in addition to oscillations as sine waves
<p>Raw 1200 LFP data sets of 60s are in /60s_125(250,500,1000)Hz_20h/12XX/eeg1_t0(1-1199) .txt. Results of tau and burst, whose state is identified by existing method (0:awake, 1:NREM, 2:REM), are in /60s_125-1000Hz_20h/12XX_m2 or S1/tau-burst_m2(s1)_thX.XXX.txt. th=threshold. Column 1:trial No., 2:state, 3:Ntau, 4:Mtau, 5:ratio of total tau, 6:number of burst, 7:mean burst, 8:Abst. Those identified by Ntau method are in /60s_125-1000Hz_20h/4state (mean per state), 4state_m2, or 4states _s1/12XX/tauburst-m2_4state_thx.XXX.txt.The state is listed in third column as 2:awake, 10:REM, 20:NREM, 30:light sleep. Data of SEF95 are in /60s_sef_4state/12XX_SEF4state_125(250,500,1000) Hz.txt.</p> <p>Raw EEG data sets of 64s are in /dogEEG/older(younger)_sev/20150XXX/50Hz_nonMovAve/20150XXX_sevX.X_int0(1,2)_cts2.txt. Results of tau and burst are contained in /dogEEG/older(younger)_sev/20150XXX/sratio_peak/non-movave/20150XXX_sratio_peak_tau-burst_thXX.XX.txt. Column 1:sevoflurane concentration, 2:int, 3:Ntau, 4:Mtau, 5:ratio of total tau, 6:number of burst, 7:mean burst, 8:Abst. Results of SEF95 are in /dogEEG/older(younger)_sev/20150XXX/50Hz_nonMovAve/20150XXX_sef95.txt. Data of maximum Ntau, minimum Abst, or Mtau=2.3, 2.5 sample interval are in /dogEEG/THnt_250Hz.</p>
The effect of migration and variation on populations of Escherichia coli adapting to complex fluctuating environments
<p class="MsoNormal"><span>Migration, a critical evolutionary force, can have contrasting effects on adaptation. It can aid as well as impede adaptation. The effects of migration on microbial adaptation have been studied primarily in simple constant environments. Very little is known about the effects of migration on adaptation to complex, fluctuating environments. In our study, we subjected replicate populations of <em><span>Escherichia coli</span></em>, adapting to complex and unpredictably fluctuating environments to different proportions of clonal ancestral immigrants. Contrary to the results from simple/constant environments, the presence of clonal immigrants reduced all measured proxies of fitness. However, migration from a source population with a greater variance in fitness resulted in no change in fitness w.r.t the no-migration control, except at the highest level of migration. Thus, the presence of variation in the immigrants could counter the adverse effects of migration in complex and unpredictably fluctuating environments. Our study demonstrates that the effects of migration are strongly dependent on the nature of the destination environment and the genetic makeup of immigrants. These results enhance our understanding of the influences of migrating populations, which could help better predict the consequences of migration.</span></p>
Supporting dataset: "Analysis of tide and offshore storm-induced water table fluctuations for structural characterization of a coastal island aquifer"
<p>Included in this repository are supporting field data and final model input files used to produce the results of the manuscript:</p> <p>Trglavcnik, V., Morrow, D., Weber, K. P., Li, L., & Robinson, C. E. (2017), "Analysis of tide and offshore storm-induced water table fluctuations for structural characterization of a coastal island aquifer."</p> <p>This dataset contains:</p> <ul> <li>SableIsland_data.xlsx <ul> <li>Data used to produce figures in the above manuscript. </li> </ul> </li> <li>Final_SS.zip <ul> <li>Input files for the final model (see Figure 3 in manuscript), steady-state SEAWAT simulation. </li> </ul> </li> <li>Final_PBC.zip <ul> <li>Input files for the final model, transient SEAWAT simulation with a sinusoidal tidal boundary implemented by the Periodic Boundary Condition package (developed for MODFLOW by Post, 2011).</li> </ul> </li> </ul> <p>All data and files are licensed under Creative Commons Attribution Share Alike 4.0 International.</p> <p> </p> <p> </p>
Membrane Fluctuation Model to Understand the Effect of the Receptor Nanoclustering on the Activation of Natural Killer Cells through Biomechanical Feedback
<p>Data for all the plots from original paper "Membrane Fluctuation Model to Understand the Effect of the Receptor Nanoclustering on the Activation of Natural Killer Cells through Biomechanical Feedback".</p>
Túngara frog call-timing decisions arise as internal rhythms interact with fluctuating chorus noise
<p>For chorusing males, optimally timing their calls relative to nearby rivals' calls and fluctuations in background chorus noise is crucial for reproductive success. A caller's acoustic environment will vary by chorus density and the properties of his chorus-mates' calls and will fluctuate unpredictably due to chorusing dynamics emerging among his chorus-mates. Thus, callers must continuously monitor moment-to-moment fluctuations in the acoustic scene they perceive at the chorus for advantageous times to call. In live experimental choruses, we investigated the factors influencing túngara frog call-timing responses to chorus-mates' calls on an interaction-by-interaction basis, revealing that intrinsic and extrinsic factors influenced call-timing decisions. Callers were more likely to overlap calls from smaller chorus-mates and chorus-mates at intermediate distances, as well as calls containing lower frequencies and exhibiting lower final amplitude minima. Consequently, variation among males in call properties led to variation in levels of call-interference received when calling in the same social environment. Additionally, callers were more likely to overlap chorus-mates' calls after experiencing extended periods of inhibition and were less likely to overlap synchronized chorus-mates' calls relative to single calls. In chorusing species, female choice is influenced by inter-caller dynamics, selecting for male call-timing strategies which, in turn, constitute the selective environment further refining these same strategies. Thus, understanding the specific factors driving call-timing decisions is essential for understanding how sexual selection operates in chorusing taxa.</p>
Replication package for: Search Complementarities, Aggregate Fluctuations, and Fiscal Policy
<p>Fernández-Villaverde J, Mandelman F, Yu Y, Zanetti F. Search complementarities, aggregate fluctuations, and fiscal policy. <em>Review of Economic Studies</em></p>
Data from: Evolutionary variation in gene conversion at the avian MHC is explained by fluctuating selection, gene copy numbers, and life history
<p>The Major Histocompatibility Complex (MHC) multigene family encodes key pathogen-recognition molecules of the vertebrate adaptive immune system. Hyper-polymorphism of MHC genes is <em>de novo</em> generated by point mutations, but new haplotypes may also arise by re-shuffling of existing variation through intra- and inter-locus gene conversion. Although the occurrence of gene conversion at the MHC has been known for decades, we still have limited understanding of its functional importance. Here, I took advantage of extensive genetic resources (~9000 sequences) to investigate a broad scale macroevolutionary patterns in gene conversion processes at the MHC across nearly 200 avian species. Gene conversion was found to constitute a universal mechanism in birds, as 83% of species showed footprints of gene conversion at either MHC class and 25% of all allelic variants were attributed to gene conversion. Gene conversion processes were stronger at MHC-II than MHC-I, but inter-specific variation at both MHC classes was explained by similar evolutionary scenarios, reflecting fluctuating selection towards different optima and drift. Gene conversion showed uneven phylogenetic distribution across birds and was driven by gene copy number variation, supporting significant role of inter-locus gene conversion processes in the evolution of the avian MHC. Finally, MHC gene conversion was stronger in species with fast life histories (high fecundity) and in long-distance migrants, likely reflecting variation in population sizes and host-pathogen coevolutionary dynamics. The results provide a robust comparative framework for understanding macroevolutionary variation in gene conversion at the avian MHC and reinforce important contribution of this mechanism to functional MHC diversity.</p>
Microplastics promote the invasiveness of invasive alien species under fluctuating water regime
<p>Microplastic pollution and alien plant invasions are two important threats to terrestrial ecosystems. Microplastics (MPs) alter the physical and chemical characteristics of soil, potentially affecting the performance of alien plants. However, previous studies have overlooked the impact of weather on invasive plants in areas polluted by MPs. With the global increase in extreme rainfall events, it is imperative to redefine the correlation between MPs and invasive plants. Here, we conducted an experiment in a climate chamber to examine the effects of MPs on the growth and development of both native and invasive alien plants under a constant and fluctuating water regime (FWR). The FWR simulated extreme water pulses during the 2016-2020 growing seasons in Wuhan, China. Our results indicated that biomass accumulation and roots development were influenced by water conditions and MPs pollution in both invasive and native species. The extent of the effects varied between the two groups of plant species. FWR promoted plant growth and fine root development in invasive plants but reduced the maximum quantum efficiency of photosystem II (<em>F</em><em><sub>v</sub></em><em>/F</em><em><sub>m</sub></em>) and nonphotochemical quenching (<em>NPQ</em>) indices of native plants. Moreover, FWR attenuated the negative effects of polybutylene succinate (PBS, degradable MPs) on biomass and root characteristics (length, surface area, and tips). FWR compensates for the negative impacts of MPs on the total and belowground biomass of the invasive species <em>Paspalum dilatatum</em> and <em>Sphagneticola trilobata</em>, but not on the native species. Consequently, invasive species showed better performance than native species in the fine-root development of biomass growth and chlorophyll fluorescence under the combined effects of MPs and FWR.</p> <p><em>Synthesis and Applications</em>. Our findings suggest that MPs pollution enhances the competitiveness of invasive alien species over the native species when exposed to pronounced dry-wet water cycle conditions, potentially affecting the composition and biodiversity of the ecosystems. Thus, controlling MPs pollution should be a part of the management strategy to conserve biodiversity and ecosystems.</p>
Subphotospheric fluctuations in magnetized radiative envelopes: contribution from unstable magnetosonic waves
<p>MESA inlists associated with <a href="https://ui.adsabs.harvard.edu/#abs/2018MNRAS.477.2286S/abstract">Koushik et al. (2018)</a>. MESA version 6974.</p> <p>Publication DOI: <a href="https://doi.org/10.1093/mnras/sty736">10.1093/mnras/sty736</a></p>
Exploring Fluctuations in Internal Quality Metrics
<p>Datasets and analysis script for the article "Exploring Fluctuations in Internal Quality Metric" submitted to ESEM'19 under double-blind review and provided as-is.</p>
Data for the publication "Singular charge fluctuations at a magnetic quantum critical point"
<p>Data sets of the figures in the publication "Singular charge fluctuations at a magnetic quantum critical point"</p> <p>Preprint: arXiv:1808.02296</p>
Figure 6 in Density, diversity, and seasonal fluctuations in soil Collembola in three differently managed ecosystems in North Khorasan, Iran
Figure 6. Seasonal changes in density (individuals per m2) of Collembola in different ecosystems.
Figure 7 in Density, diversity, and seasonal fluctuations in soil Collembola in three differently managed ecosystems in North Khorasan, Iran
Figure 7. Seasonal changes in Diversity (H´) of Collembola in different ecosystems.
Figure 1 in Short-time salinity fluctuations are strong activators of oxidative stress in Mediterranean mussel (Mytilus galloprovincialis)
Figure 1. Scheme illustrating the experimental design.
Greenland-wide assessment of supraglacial lake area fluctuations between 2017 and 2022
<p>The area of supraglacial lake (SGL) on Greenland ice sheet over 2017-2022 melting season has been extracted from approximately 300,000 passive optical satellite images. Each time series consists of four columns of decimal time, standard date, SGL area, and the corresponding uncertainty, respectively. The SGL area was calculated based on the SGL occurrence grids, and a total of 3,006 grids with valid observations were obtained.</p>
Pleistocene climatic fluctuations promoted alternative evolutionary histories in Phytelephas aequatorialis, an endemic palm from western Ecuador
<p class="CxSpFirst"><b>Aim: </b>Pleistocene (2.58 Ma – 11.7 ka) climatic fluctuations have shaped intraspecific genetic patterns worldwide; however, their manifestation in many regions remains unknown. In order to determine the impact of Pleistocene climatic fluctuations on the tropical rain forests of western Ecuador, we explored the evolutionary history of the endemic palm <i>Phytelephas aequatorialis</i>.</p> <p class="CxSpMiddle"><b>Location: </b>Western Ecuador, northwestern South America.</p> <p class="CxSpMiddle"><b>Taxon: </b><i>Phytelephas aequatorialis </i>(Arecaceae).</p> <p class="CxSpMiddle"><b>Methods:</b> 176 nuclear genes were sequenced in 91 individuals for phylogenomic and population structure analyses. The time of divergence between identified genetic lineages was estimated using a coalescent phylogenomic analysis. Paleoecological niche modelling analyses were performed to determine areas of historical climatic suitability since the Last Glacial Maximum (LGM; 22 ka) that potentially acted as forest refugia during the Pleistocene. A Wilcoxon test and Pearson correlations were used to explore how current levels of genetic diversity (<i>Hs</i>) have been shaped by several paleoclimatic and geographic factors.</p> <p class="CxSpMiddle"><b>Results:</b> Phylogenomic and population structure analyses revealed two genetic lineages with a north-south distribution, which diverged 1.14 Ma during the Pleistocene. Two potential Pleistocene refugia were identified in the Pacific coast of Ecuador and in the Andean foothills of southwestern Ecuador, whose distribution agrees with the spatial location of the two lineages. Within the Andean foothills, <i>Hs</i> was lower for the southern lineage than for the northern lineage. <i>Hs</i> significantly increased with decreasing latitude within the whole species distribution.</p> <p class="CxSpMiddle"><b>Main conclusions: </b>Pleistocene climatic fluctuations promoted intraspecific divergence in <i>P. aequatorialis </i>within the rain forests of western Ecuador. The Andean foothills of southwestern Ecuador could be an important spot for rain forest evolution because they potentially remained climatically suitable through the Pleistocene. Lower genetic diversity in the southern lineage, which apparently remained isolated in the Andean foothills during glacial cycles, adds evidence to the presence of a forest refugium in southwestern Ecuador. The geographic pattern in genetic diversity suggests that <i>P. aequatorialis </i>colonized western Ecuador from the north. This study supports the role of Pleistocene climatic fluctuations in promoting intraspecific divergence, and for the first time, we show their impact west of the Andes.</p>
Data for: Latent functional diversity may accelerate microbial community responses to temperature fluctuations
<p>How complex microbial communities respond to climatic fluctuations remains an open question. Due to their relatively short generation times and high functional diversity, microbial populations harbor great potential to respond as a community through a combination of strain-level phenotypic plasticity, adaptation, and species sorting. However, the relative importance of these mechanisms remains unclear. We conducted a laboratory experiment to investigate the degree to which bacterial communities can respond to changes in environmental temperature through a combination of phenotypic plasticity and species sorting alone. We grew replicate soil communities from a single location at six temperatures between 4°C and 50°C. We found that phylogenetically- and functionally-distinct communities emerge at each of these temperatures, with <em>K</em>-strategist taxa favoured under cooler conditions, and <em>r</em>-strategist taxa under warmer conditions. We show that this dynamic emergence of distinct communities across a wide range of temperatures (in essence, community-level adaptation), is driven by the resuscitation of latent functional diversity: the parent community harbors multiple strains pre-adapted to different temperatures that are able to "switch on" at their preferred temperature without immigration or adaptation. Our findings suggest that microbial community function in nature is likely to respond rapidly to climatic temperature fluctuations through shifts in species composition by resuscitation of latent functional diversity.</p>
Fluctuations in resource availability shape the competitive balance among non-native plant species
<p>Fluctuating resource availability plays a critical role in determining non-native plant invasions by mediating the competitive balance between non-native and native species. However, the impact of fluctuating resource availability on interactions among non-native species remains largely unknown. This represents a barrier to understanding invasion mechanisms, particularly in habitats that harbor multiple non-native species with different responses to fluctuating resource availability. To examine the responses of non-native plant species to nutrient fluctuations, we compared the growth of each of 12 non-native species found to be common in local natural areas to nutrients supplied at a constant rate or supplied as a single large pulse in a pot experiment. We found that seven species produced more biomass with pulsed nutrients compared to constant nutrients (hereafter 'benefitting species'), while the other five species did not differ between nutrient enrichment treatments (hereafter 'non-benefitting species'). To investigate how nutrient fluctuations influence the interactions among non-native plant species, we established experimental non-native communities in the field with two benefitting and two non-benefitting non-native species. Compared with constant nutrient supply, the single large pulse of nutrients did not influence community biomass, but strongly increased the biomass and cover of the benefitting species and decreased those of the non-benefitting species. Furthermore, the benefitting species had higher leaf N content and greater plant height when nutrients were supplied as a single large pulse than at a constant rate, whereas the non-benefitting species showed no differences in leaf N content and were shorter when nutrients were supplied as a single large pulse than at a constant rate. Our results add to the growing evidence that the individual responses of non-native species to nutrient fluctuation are species-specific. More importantly, benefitting species were favored by nutrients coming in a pulse, while non-benefitting ones were favored by nutrients coming constantly when they grew together. This suggests that nutrient fluctuations can mediate the competitive balance among non-native plants and may thus determine their invasion success in a community harbouring multiple non-native plant species.</p>
ScienceDex guides
Understand access before you commit
These curated guides explain access requirements, typical timelines, costs, and reuse considerations for widely used research datasets.
Allen Brain Atlas
Allen Brain Atlas is an Allen Institute collection of brain map atlases, datasets, APIs, and analysis tools covering mouse, human, and non-human primate brain resources.
Annotated Behaviour and Observability Dataset (ABODe)
ABODe is a University of Edinburgh DataShare dataset for behavior classification in group-housed mice using home-cage video, identities, bounding boxes, ground-plate positions, and annotator labels.
DANDI Archive for NWB datasets
DANDI is a BRAIN Initiative archive for publishing and sharing neurophysiology data, including electrophysiology, optophysiology, and behavioral data packaged as NWB and related standards.
International Brain Laboratory public data
The International Brain Laboratory public data releases expose standardized mouse decision-making experiments, including Neuropixels recordings, widefield calcium imaging, behavior, and session metadata accessed through the ONE API.
OpenNeuro
OpenNeuro is a free, open platform for sharing neuroimaging datasets, with public search, dataset pages, and download paths for web, S3, DataLad, and the OpenNeuro CLI.