Recognition of the importance of intraspecific variation in ecological processes has been growing, but empirical studies and models of global change have only begun to address this issue in detail. ...This review discusses sources and patterns of intraspecific trait variation and their consequences for understanding how ecological processes and patterns will respond to global change. We examine how current ecological models and theories incorporate intraspecific variation, review existing data sources that could help parameterize models that account for intraspecific variation in global change predictions, and discuss new data that may be needed. We provide guidelines on when it is most important to consider intraspecific variation, such as when trait variation is heritable or when nonlinear relationships are involved. We also highlight benefits and limitations of different model types and argue that many common modeling approaches such as matrix population models or global dynamic vegetation models can allow a stronger consideration of intraspecific trait variation if the necessary data are available. We recommend that existing data need to be made more accessible, though in some cases, new experiments are needed to disentangle causes of variation.
Most metazoan microRNAs (miRNAs) target many genes for repression, but the nematode lsy-6 miRNA is much less proficient. Here we show that the low proficiency of lsy-6 can be recapitulated in HeLa ...cells and that miR-23, a mammalian miRNA, also has low proficiency in these cells. Reporter results and array data indicate two properties of these miRNAs that impart low proficiency: their weak predicted seed-pairing stability (SPS) and their high target-site abundance (TA). These two properties also explain differential propensities of small interfering RNAs (siRNAs) to repress unintended targets. Using these insights, we expand the TargetScan tool for quantitatively predicting miRNA regulation (and siRNA off-targeting) to model differential miRNA (and siRNA) proficiencies, thereby improving prediction performance. We propose that siRNAs designed to have both weaker SPS and higher TA will have fewer off-targets without compromised on-target activity.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Increasing aridity as a result of climate change is expected to exacerbate tree mortality. Reducing forest basal area - the cross-sectional area of tree stems within a given ground area - can ...decrease tree competition, which may reduce drought-induced tree mortality. However, neither the magnitude of expected mortality increases, nor the potential effectiveness of basal area reduction, has been quantified in dryland forests such as those of the drought-prone Southwest US. We used thousands of repeatedly measured forest plots to show that unusually warm and dry conditions are related to high tree mortality rates and that mortality is positively related to basal area. Those relationships suggest that while increasing high temperature extremes forecasted by climate models may lead to elevated tree mortality during the 21st century, future tree mortality might be partly ameliorated by reducing stand basal area. This adaptive forest management strategy may provide a window of opportunity for forest managers and policy makers to guide forest transitions to species and/or genotypes more suited to future climates.
Co-production: towards a utopian approach Bell, David M.; Pahl, Kate
International journal of social research methodology,
01/2018, Letnik:
21, Številka:
1
Journal Article
Recenzirano
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This article outlines how co-production might be understood as a utopian method, which both attends to and works against dominant inequalities. It suggests that it might be positioned 'within, ...against, and beyond' current configurations of power in academia and society more broadly. It develops this argument by drawing on recent research funded through the UK's Connected Communities programme, led by the Arts and Humanities Research Council; and by attending to arguments from the field of Utopian Studies. It explores particular issues of power and control within the field of co-production, acknowledging that neoliberalism both constrains and co-opts such practice; and explores methodological and infrastructural issues such that its utopian potential might be realised.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Diet has a profound effect on tissue regeneration in diverse organisms, and low caloric states such as intermittent fasting have beneficial effects on organismal health and age-associated loss of ...tissue function. The role of adult stem and progenitor cells in responding to short-term fasting and whether such responses improve regeneration are not well studied. Here we show that a 24 hr fast augments intestinal stem cell (ISC) function in young and aged mice by inducing a fatty acid oxidation (FAO) program and that pharmacological activation of this program mimics many effects of fasting. Acute genetic disruption of Cpt1a, the rate-limiting enzyme in FAO, abrogates ISC-enhancing effects of fasting, but long-term Cpt1a deletion decreases ISC numbers and function, implicating a role for FAO in ISC maintenance. These findings highlight a role for FAO in mediating pro-regenerative effects of fasting in intestinal biology, and they may represent a viable strategy for enhancing intestinal regeneration.
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•Fasting induces fatty acid oxidation (FAO) in intestinal stem and progenitor cells•Aging reduces ISC numbers and function, correlating with decreased FAO•PPAR/CPT1a-mediated FAO augments ISC function in aging and during regeneration•PPARδ agonists boost and restore ISC and progenitor function in young and old age
Mihaylova et al. show that short-term fasting promotes intestinal stem and progenitor cell function in young and aged mice by inducing a robust fatty acid oxidation (FAO) program. PPARδ agonists emulate these effects, showing that fatty acid metabolism has positive effects on young and old ISCs.
Socioeconomic position (SEP) is a multi-dimensional construct reflecting (and influencing) multiple socio-cultural, physical, and environmental factors. In a sample of 286,301 participants from UK ...Biobank, we identify 30 (29 previously unreported) independent-loci associated with income. Using a method to meta-analyze data from genetically-correlated traits, we identify an additional 120 income-associated loci. These loci show clear evidence of functionality, with transcriptional differences identified across multiple cortical tissues, and links to GABAergic and serotonergic neurotransmission. By combining our genome wide association study on income with data from eQTL studies and chromatin interactions, 24 genes are prioritized for follow up, 18 of which were previously associated with intelligence. We identify intelligence as one of the likely causal, partly-heritable phenotypes that might bridge the gap between molecular genetic inheritance and phenotypic consequence in terms of income differences. These results indicate that, in modern era Great Britain, genetic effects contribute towards some of the observed socioeconomic inequalities.
Aim To determine if differences in climate envelopes for six coniferous tree species and two life stages (trees and seedlings) suggest a potential for species range contractions, expansions or shifts ...in response to climate change and if these patterns differ between subalpine (i.e. cool-climate) and montane (i.e. warm-climate) species. Location The dry domain of the western United States. Methods Using data from the Forest Inventory and Analysis National Program, we quantified the relationship between probability of occurrence and climate for adults and seedlings of each species with a Bayesian logistic regression. Assuming that distributional differences between life stages highlight shifting regeneration patterns relative to adult trees, we assessed differences between seedlings and adult trees based on predicted probabilities of occurrence and climate envelope boundaries. Results Differences between occurrence probabilities for seedlings and adults were greatest for montane, as opposed to subalpine, species and along range margins, especially in the southern and western portions of the study area. Climate envelope boundaries of seedlings differed from adult trees most frequently in montane species and often suggested range contractions or range shifts, as opposed to range expansion. Main conclusions Our results indicated that climate-induced contractions and shifts in seedling distribution in response to recent change are already under way and are particularly severe in montane tree species. While adult trees may persist for hundreds of years without significant regeneration, tree species ranges will eventually contract where tree regeneration fails.
We synthesize insights from current understanding of drought impacts at stand‐to‐biogeographic scales, including management options, and we identify challenges to be addressed with new research. ...Large stand‐level shifts underway in western forests already are showing the importance of interactions involving drought, insects, and fire. Diebacks, changes in composition and structure, and shifting range limits are widely observed. In the eastern US, the effects of increasing drought are becoming better understood at the level of individual trees, but this knowledge cannot yet be confidently translated to predictions of changing structure and diversity of forest stands. While eastern forests have not experienced the types of changes seen in western forests in recent decades, they too are vulnerable to drought and could experience significant changes with increased severity, frequency, or duration in drought. Throughout the continental United States, the combination of projected large climate‐induced shifts in suitable habitat from modeling studies and limited potential for the rapid migration of tree populations suggests that changing tree and forest biogeography could substantially lag habitat shifts already underway. Forest management practices can partially ameliorate drought impacts through reductions in stand density, selection of drought‐tolerant species and genotypes, artificial regeneration, and the development of multistructured stands. However, silvicultural treatments also could exacerbate drought impacts unless implemented with careful attention to site and stand characteristics. Gaps in our understanding should motivate new research on the effects of interactions involving climate and other species at the stand scale and how interactions and multiple responses are represented in models. This assessment indicates that, without a stronger empirical basis for drought impacts at the stand scale, more complex models may provide limited guidance.
Evolution generates a remarkable breadth of living forms, but many traits evolve repeatedly, by mechanisms that are still poorly understood. A classic example of repeated evolution is the loss of ...pelvic hindfins in stickleback fish (
). Repeated pelvic loss maps to recurrent deletions of a pelvic enhancer of the
gene. Here, we identify molecular features contributing to these recurrent deletions.
enhancer sequences form alternative DNA structures in vitro and increase double-strand breaks and deletions in vivo. Enhancer mutability depends on DNA replication direction and is caused by TG-dinucleotide repeats. Modeling shows that elevated mutation rates can influence evolution under demographic conditions relevant for sticklebacks and humans. DNA fragility may thus help explain why the same loci are often used repeatedly during parallel adaptive evolution.
•We characterized annual rates of forest disturbance between 1985 and 2012.•Landsat time series were visually interpreted, with support of ancillary data.•A probability design was used to scale ...estimates and provide uncertainties.•Harvest was the most important disturbance agent class prior to the mid-90s.•Forest decline is now more important than harvest as the dominant agent class.
Evidence of shifting dominance among major forest disturbance agent classes regionally to globally has been emerging in the literature. For example, climate-related stress and secondary stressors on forests (e.g., insect and disease, fire) have dramatically increased since the turn of the century globally, while harvest rates in the western US and elsewhere have declined. For shifts to be quantified, accurate historical forest disturbance estimates are required as a baseline for examining current trends. We report annual disturbance rates (with uncertainties) in the aggregate and by major change causal agent class for the conterminous US and five geographic subregions between 1985 and 2012. Results are based on human interpretations of Landsat time series from a probability sample of 7200 plots (30m) distributed throughout the study area. Forest disturbance information was recorded with a Landsat time series visualization and data collection tool that incorporates ancillary high-resolution data. National rates of disturbance varied between 1.5% and 4.5% of forest area per year, with trends being strongly affected by shifting dominance among specific disturbance agent influences at the regional scale. Throughout the time series, national harvest disturbance rates varied between one and two percent, and were largely a function of harvest in the more heavily forested regions of the US (Mountain West, Northeast, and Southeast). During the first part of the time series, national disturbance rates largely reflected trends in harvest disturbance. Beginning in the mid-90s, forest decline-related disturbances associated with diminishing forest health (e.g., physiological stress leading to tree canopy cover loss, increases in tree mortality above background levels), especially in the Mountain West and Lowland West regions of the US, increased dramatically. Consequently, national disturbance rates greatly increased by 2000, and remained high for much of the decade. Decline-related disturbance rates reached as high as 8% per year in the western regions during the early-2000s. Although low compared to harvest and decline, fire disturbance rates also increased in the early- to mid-2000s. We segmented annual decline-related disturbance rates to distinguish between newly impacted areas and areas undergoing gradual but consistent decline over multiple years. We also translated Landsat reflectance change into tree canopy cover change information for greater relevance to ecosystem modelers and forest managers, who can derive better understanding of forest-climate interactions and better adapt management strategies to changing climate regimes. Similar studies could be carried out for other countries where there are sufficient Landsat data and historic temporal snapshots of high-resolution imagery.
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