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1,610 results for “ratio”
Offspring sex-ratios are stable across the life-course in Drosophila simulans
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Expansion of wastewater-based disease surveillance to improve health equity in California’s Central Valley: Sequential shifts in case-to-wastewater and hospitalization-to-wastewater ratios
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Ant Isotope ratios at the Kellogg Biological Station, Hickory Corners, MI (2018)
Dataset AbstractThis is data supporting the publication: Jackson A. Helms IV et.al 2020. “Bioenergy landscapes drive trophic shifts in generalist ants” in the Journal of Animal Ecology. These data document tissue stable isotope ratios of C and N in plants and invertebrates collected by hand or in pitfall traps during the 2018 growing season from the Biofuel Cropping System Experiment (BCSE) plots and the GLBRC Scale-Up Experiment.original data source http://lter.kbs.msu.edu/datasets/199
Ratio of 18O to 16O Stable Isotopes in Tree Stem Cores at HJA, HFR, NWT, CWT, LUQ, and Barro Colorado Island
Patterns of biodiversity, such as the increase toward the tropics and the peaked curve during ecological succession, are fundamental phenomena for ecology. Such patterns have multiple, interacting causes, but temperature emerges as a dominant factor across organisms from microbes to trees and mammals, and across terrestrial, marine, and freshwater environments. However, there is little consensus on the underlying mechanisms, even as global temperatures increase and the need to predict their effects becomes more pressing. The purpose of this project is to generate and test theory for how temperature impacts biodiversity through its effect on biochemical processes and metabolic rate. A combination of standardized surveys in the field and controlled experiments in the field and laboratory measure diversity of three taxa -- trees, invertebrates, and microbes -- and key biogeochemical processes of decomposition in seven forests distributed along a geographic gradient of increasing temperature from cold temperate to warm tropical. The most abundant tree species (by basal area) were sampled at each experimental site (HJA, HFR, NWT, CWT, LUQ, and Barro Colorado Island) for ratio of stable isotopes of 18 Oxygen to 16 Oxygen in parts per million from ground and homogenized tree stem cores as part of a macrosystems biodiversity and latitude project supported by the National Science Foundation under Cooperative Agreement DEB#1065836. .
Standardized Incidence Ratio of developing a malignancy in the Eye, Orbit and their adnexa after a first primary elsewhere in the body.
<p>Standardized Incidence Ratio of Eye, Orbit and their adnexa after a first primary elsewhere in the body.</p>
CompressGraph: Knowledge about compression algorithms, tools, formats, ratios and runtime behaviour
<p>Machine-readable dataset to determine the best compression settings for a given goal such as "fastest compression" or "fastest search over compressed data". Graph model (JSON + auto-derived Dot format) along with CSV measurement results of 13 compression tools and 30 tool-configuration-search combinations.</p> <p>Associated publication: Josef Spillner, «Comparison and Model of Compression Techniques for Smart Cloud Log File Handling», CCCI 2020.</p> <p>This dataset also contains a snapshot of the associated software prototypes.<br> </p>
Data from: Are human natal sex ratio differences across the world adaptive? A test of Fisher's principle
<p>Fisher's principle states that natural selection favours an equal number of male and female births at the population level, unless there are sex differences in rearing costs or sex differences in mortality before the end of the period of parental investment. Sex differences in rearing costs should be more pronounced in low- than in high-resource settings. We, therefore, examined whether human development index and sex differences in child mortality contribute to the natural variation in human sex ratio at birth across the globe. As predicted by Fisher's principle, the proportion of male births increased with both increasing male-biased childhood mortality and level of development of each country. However, these relationships were absent after accounting for spatial autocorrelation in the residuals, which our inference is conditioned on. This work shows how the failure to account for residual spatial autocorrelation can lead to incorrect conclusions regarding support for predictions from sex allocation theory.</p>
Divergence of responses to variable socio-sexual environments in laboratory populations of Drosophila melanogaster evolving under altered operational sex-ratios
<p class="BodyA">Post-copulatory sexual selection (PSS) is an important selective force that determines fitness in polyandrous species. PSS can be intense in some cases and can drive the evolution of remarkable ejaculate properties. In males, investment in ejaculate plays an important role in the outcome of PSS. Thus, males are expected to adaptively tailor their ejaculate according to the perceived competition in their vicinity. Plastic responses in ejaculate investment to variation in intra-sexual competition are disparate and widespread in males.</p> <p class="BodyA"><span>We investigated the evolution of plasticity in reproductive traits using <i>Drosophila melanogaster</i> populations evolving for more than 150 generations under male- or female-biased sex ratios.</span> <span>When exposed to different numbers of competitors early in their life, males from these two regimes responded differently in terms of their copulation duration and sperm competitive ability. In addition, the effect of this early life experience wore off at different rates in males of male-biased and female-biased regimes with increasing time from the removal of competitive cues. Furthermore, our study finds that males change their reproductive strategies depending upon the identity of rival males. Together, our results provide evidence of the evolution of male reproductive investment that depends on socio-sexual cues experienced early in life. </span></p>
The plot thickens: Haploid and triploid-like thalli, hybridization, and biased mating type ratios in Letharia
<p>The study of the reproductive biology of lichen fungal symbionts has been traditionally challenging due to their complex and symbiotic lifestyles. Against the common belief of haploidy, a recent genomic study found a triploid-like signal in <em>Letharia</em>. Here, we used genomic data from a pure culture and from thalli, together with a PCR survey of the MAT locus, to infer the genome organization and reproduction in <em>Letharia</em>. We found that the read count variation in the four <em>Letharia</em> specimens, including the pure culture derived from a single sexual spore of <em>L. lupina</em>, is consistent with haploidy. By contrast, the <em>L. lupina </em>read counts from a thallus' metagenome are triploid-like. Characterization of the mating-type locus revealed a conserved heterothallic configuration across the genus, along with auxiliary genes that we identified. We found that the mating-type distributions are balanced in North America for <em>L. vulpina</em> and <em>L. lupina</em>, suggesting widespread sexual reproduction, but highly skewed in Europe for <em>L. vulpina</em>, consistent with predominant asexuality. Taken together, we propose that <em>Letharia</em> fungi are heterothallic and typically haploid, and provide evidence that triploid-like individuals are rare hybrids between <em>L. lupina</em> and an unknown <em>Letharia</em> lineage, reconciling classic systematic and genetic studies with recent genomic observations.</p>
Data from: Sex ratio of Western Bluebirds Sialia mexicana is mediated by phenology and clutch size
<p><span><span><span><span><span><span><span><span><span><span><span>Mothers may produce more of one sex to maximize their fitness if there are differences in the cost of producing each sex or there are differences in their relative reproductive value. We tested if breeding date, clutch size and drought conditions influenced offspring sex ratios in Western Bluebirds (<em>Sialia mexicana</em>) from 1997 to 2017. We found that hatch dates late in the breeding season were associated with the production of more females. When clutch size was taken into account, small clutches yielded significantly more females late in the breeding season compared to the early and middle parts of the breeding season that produced significantly more males. Large clutches early in the season tended to produce more females, although this was not significant. Drought severity was not correlated with sex ratio adjustment. </span></span></span></span></span></span></span></span></span></span></span></p>
Data for: Female-biased sex ratios in urban centres create a fertility trap in post war Finland
<p>Because sex ratios are a key factor regulating mating success and subsequent fitness both across and within species, there is widespread interest in how population-wide sex ratio imbalances affect marriage markets and the formation of families in human societies. Although most modern cities have more women than men and suffer from low fertility rates, the effects of female-biased sex ratios have garnered less attention than male-biased ratios. Here, we analyze how sex ratios are linked to marriages, reproductive histories, dispersal and urbanization by taking advantage of a natural experiment in which an entire population was forcibly displaced during World War II to other local Finnish populations of varying sizes and sex ratios. Using a discrete time-event generalised linear mixed-effects model, and including factors that change across time, such as annual sex ratio, we show how sex ratios, reproduction, and migration are connected in a female-dominated environment. Young childless women migrated toward urban centers where work was available to women, and away from male-biased rural areas. In such areas where there were more females, women were less likely to start reproduction. Despite this constraint, women showed little flexibility in mate choice, with no evidence for an increase in partner age difference in female-biased areas. We propose that together these behaviours and conditions combine to generate an 'urban fertility trap' which may have important consequences for our understanding of the fertility dynamics of today including the current fertility decline across the developed world.</p>
Data from: Effects of parasitic sex-ratio distorters on host genetic structure in the Armadillidium vulgare-Wolbachia association
In the pill bug Armadillidium vulgare (Crustacea, Oniscidea) Wolbachia facilitates its spread through vertical transmission via the eggs by inducing feminization of genetic males. The spread of feminizing Wolbachia within and across populations is therefore expected to influence mtDNA genetic structure by hitchhiking. To test this hypothesis, we analysed nuclear and mtDNA genetic structure, and Wolbachia prevalence in 13 populations of the pill bug host. Wolbachia prevalence (ranging from 0 to 100% of sampled females) was highly variable among populations. All three Wolbachia strains previously observed in A. vulgare were present (wVulC, wVulM and wVulP) with wVulC being the most prevalent (9 out of 13 populations). The host showed a genetic structure on five microsatellite loci that is compatible with isolation by distance. The strong genetic structure observed on host mtDNA was correlated to Wolbachia prevalence: three mitotypes were in strong linkage disequilibrium with the three strains of Wolbachia. Neutrality tests showed that the mtDNA polymorphism is not neutral and we thus suggest that this unusual pattern of mtDNA polymorphism found in A. vulgare was due to Wolbachia.
Data from: How to calculate the non-synonymous to synonymous rate ratio of protein-coding genes under the Fisher-Wright mutation-selection framework
First principles of population genetics are used to obtain formulae relating the non-synonymous to synonymous substitution rate ratio to the selection coefficients acting at codon sites in protein-coding genes. Two theoretical cases are discussed and two examples from real data (a chloroplast gene and a virus polymerase) are given. The formulae give much insight into the dynamics of non-synonymous substitutions and may inform the development of methods to detect adaptive evolution.
Data from: Caste ratio adjustments in response to perceived and realised competition in parasites with division of labour
1. Colonial organisms with division of labour are assumed to achieve increased colony-level efficiency in task performance through functional specialisation of individuals into distinct castes. In social insects, ratios of individuals in different castes can adjust adaptively in response to external threats. However, whether flexibility in caste ratio also occurs in other social organisms with division of labour remains unclear. Some parasitic trematodes, in which clonal colonies within the snail intermediate host comprise a reproductive caste and a soldier caste, offer good systems to test the general nature of adaptive caste ratio adjustments. 2. Using the trematode Philophthalmus sp. as model, we test whether trematode colonies shift their composition toward more soldiers when exposed to a sustained risk of invasion by a competitor parasite species, and/or when experiencing sustained, active competition. We also quantify the colony-level fitness impact of caste ratio adjustments, measured as the colony's output of larval infective stages. 3. We conducted two long-term laboratory experiments on within-snail trematode colonies. First, snails harbouring Philophthalmus colonies were exposed to different levels of invasion risk by another trematode species, Maritrema novaezealandense. Second, the structure of Philophthalmus colonies was quantified after a year-long period of within-snail competition with the other trematode species. 4. When facing the risk of invasion by a competitor, independently of the level of risk, Philophthalmus colonies showed a significant shift toward producing more soldiers, resulting in altered caste ratio. Similarly, when experiencing actual competition by another trematode established in the same snail, Philophthalmus colonies also adjusted by producing significantly more soldiers. Greater investments in defense via more soldiers had negative impacts on the establishment and size of the competitor's colonies. Nevertheless, the presence of the competitor reduced the fitness (output of infective stages) of Philophthalmus colonies, although the production of more soldiers mitigated that effect. 5. Our findings demonstrate that trematode colonies with division of labour are capable of adaptive caste ratio adjustments in response to both the perceived threat of competition, and actual competition, with trade-offs against reproductive success only apparent when soldier numbers are very high. Combined with results on social insects, our study suggests parallel adaptations of colonial organisms in phylogenetically disparate organisms.
Data from: Modified antibiotic adjuvant ratios can slow and steer the evolution of resistance: Co-amoxiclav as a case study
As antibiotic resistance spreads, developing sustainable methods to restore the efficacy of existing antibiotics is increasingly important. One widespread method is to combine antibiotics with synergistically acting adjuvants that inhibit resistance mechanisms, allowing drug killing. Here we use co-amoxiclav (a clinically important combination of the -lactam antibiotic amoxicillin and the -lactamase inhibitor clavulanate) to ask whether treatment efficacy and resistance evolution can be decoupled via component dosing modifications. A simple mathematical model predicts that different ratios of these two drug components can produce distinct evolutionary responses irrespective of initial efficacy. We test this hypothesis by selecting Escherichia coli with a plasmid encoded -lactamase (CTX-M-14), against different compositions of amoxicillin and clavulanate. Consistent with our theory, we found that while resistance evolved under all conditions, the component ratio influenced both the rate and mechanism of resistance evolution. Specifically, we found that the current clinical practice of high amoxicillin to clavulanate ratios resulted in the most rapid adaptation to antibiotics via gene dosing responses. Increased plasmid copy number allowed E. coli to increase -lactamase dosing and effectively titrate out low quantities of clavulanate, restoring amoxicillin resistance. In contrast, high clavulanate ratios were more robust - plasmid copy number did not increase, although porin or efflux resistance mechanisms were found, as in all drug ratios. Our results indicate that by changing the ratio of adjuvant to antibiotic we can slow and steer the path of resistance evolution. We therefore suggest using increased adjuvant dosing regimens to slow the rate of resistance evolution.
Data from: Sex ratio and gamete size across eastern North America in Dictyostelium discoideum, a social amoeba with three sexes
Theory indicates that numbers of mating types should tend towards infinity or remain at two. The social amoeba, Dictyostelium discoideum, however, has three mating types. It is therefore a mystery how this species has broken the threshold of two mating types, but has not increased towards a much higher number. Frequency dependent selection on rare types in combination with isogamy, a form of reproduction involving gametes similar in size, could explain the evolution of multiple mating types in this system. Other factors, such as drift, may be preventing the evolution of more than three. We first looked for evidence of isogamy by measuring gamete size associated with each type. We found no evidence of size dissimilarities between gametes. We then looked for evidence of balancing selection, by examining mating type distributions in natural populations and comparing genetic differentiation at the mating type locus to that at more neutral loci. We found that mating type frequency varied among the three populations we examined, with only one of the three showing an even sex ratio, which does not support balancing selection. However, we found more population structure at neutral loci than the mating type locus, suggesting that the three mating types are indeed maintained at intermediate frequencies by balancing selection. Overall, the data are consistent with balancing selection acting on D. discoideum mating types, but with a sufficiently weak rare sex advantage to allow for drift, a potential explanation for why these amoebae have only three mating types.
Data from: Female density-dependent chemical warfare underlies fitness effects of group sex ratio in flour beetles
In animals, skewed sex ratios can affect individual fitness either via sexual (e.g. intersexual conflict or intrasexual mate competition) or non-sexual interactions (e.g. sex-specific resource competition). Because most analyses of sex ratio focus on sexual interactions, the relative importance of sexual vs. non-sexual mechanisms remains unclear. We tested both mechanisms in the flour beetle Tribolium castaneum, where male-biased sex ratios increase female fitness relative to unbiased or female-biased groups. Although flour beetles show both sexual and non-sexual (resource) competition, we found that sexual interactions did not explain female fitness. Instead, female fecundity was dramatically reduced even after a brief exposure to flour conditioned by other females. Earlier studies suggested that secreted toxins might mediate density-dependent population growth in flour beetles. We identified ethyl- and methyl- benzoquinone (EBQ and MBQ; "quinones"), as components of adult stink glands that regulate female fecundity. In female-biased groups (i.e. at high female density), females upregulated quinones and suppressed each other's reproduction. In male-biased groups, low female density and associated low quinone levels maximized fecundity. Thus, females appear to use quinones as weapons for female-specific, density-dependent interference competition. Our results underscore the importance of non-sexual interference competition that may often underlie the fitness consequences of skewed sex ratios.
Data from: Quantity over quality: light intensity, but not red/far-red ratio, affects extrafloral nectar production in Senna mexicana var. chapmanii
Extrafloral nectar (EFN) mediates food-for-protection mutualisms between plants and insects and provides plants with a form of indirect defense against herbivory. Understanding sources of variation in EFN production is important because such variations affect the number and identity of insect visitors and the effectiveness of plant defense. Light represents a potentially crucial tool for regulating resource allocation to defense, as it not only contributes energy but may help plants to anticipate future conditions. Low red/far-red (R/FR) light ratios can act as a signal of the proximity of competing plants. Exposure to such light ratios has been shown to promote competitive behaviors that coincide with reduced resource allocation to direct chemical defenses. Little is known, however, about how such informational light signals might affect indirect defenses such as EFN, and the interactions that they mediate. Through controlled glasshouse experiments, we investigated the effects of light intensity, and R/FR light ratios, on EFN production in Senna mexicana var. chapmanii. Plants in light-limited conditions produced significantly less EFN, and leaf damage elicited increased EFN production regardless of light conditions. Ratios of R/FR light, however, did not appear to affect EFN production in either damaged or undamaged plants. Understanding the effects of light on indirect defenses is of particular importance for plants in the threatened pine rockland habitats of south Florida, where light conditions are changing in predictable ways following extensive fragmentation and subsequent mismanagement. Around 27% of species in these habitats produce EFN and may rely on insect communities for defense.
Data from: Comparative analyses of sex-ratio variation in dioecious flowering plants
Dioecious plant species commonly exhibit deviations from the equilibrium expectation of 1:1 sex ratio, but the mechanisms governing this variation are poorly understood. Here, we use comparative analyses of 243 species, representing 123 genera and 61 families to investigate ecological and genetic correlates of variation in the operational (flowering) sex ratio. After controlling for phylogenetic non-independence, we examined the influence of growth form, clonality, fleshy fruits, pollen and seed dispersal vector, and the possession of sex chromosomes on sex-ratio variation. Male-biased flowering sex ratios were twice as common as female-biased ratios. Male bias was associated with long-lived growth forms (e.g. trees) and biotic seed dispersal and fleshy fruits, whereas female bias was associated with clonality, especially for herbaceous species, and abiotic pollen dispersal. Female bias occurred in species with sex chromosomes and there was some evidence for a greater degree of bias in those with heteromorphic sex chromosomes. Although the role of interactions among these correlates require further study, our results indicate that sex-based differences in costs of reproduction, pollen and seed dispersal mechanisms and sex chromosomes can each play important roles in affecting flowering sex ratios in dioecious plants.
Data from: Experimental measurement of the growth costs and benefits of clonal integration of Zoysia japonica in habitats with various N/P ratios
A small number of previous studies investigating the potential advantages of clonal integration, have focused on the measurement of the costs and benefits of clonal integration at various N/P ratios. Clonal plants adaptively respond to abiotic stress but to date little is known about at what level clonal integration is beneficial or costly at various conditions. To study the costs and benefits of clonal integration on the clonal growth of Zoysia japonica, the studied species was grown under three ratios of N:P (N:P≈7, 14:1 and 21:1), and four types of stolon severing treatments (connected stolon CS, light severing LS, moderate severing MS, serious severing SS) were implemented. The results showed that Z. japonica performed best at a low ratio of N:P (N:P≈7:1). Under the stolons connected CS, the growth of primary A-ramets, multiple-nodes and stolons benefited by clonal integration; however, the growth of primary B-ramets on the primary stolons, A and B ramet significantly declined (p < 0.05). Under moderate stolon severing treatment MS7:1 (N:P≈7), the clonal integration showed most cost effective compared to all other treatments. On the whole, with increasing stolon severing intensity, the cost of clonal integration increased and the clonal growth of Z. japonica declined significantly. The pattern of biomass allocation may be useful for Z. japonica to adapt to the various environments, and clonal integration plays a significant role under adverse environmental conditions.
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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.