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1.
PLoS One ; 19(3): e0299539, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38451981

RESUMEN

Weeds are increasingly documented with evolved resistance to herbicides globally. Three species have been reported as resistant in maize crops in New Zealand: Chenopodium album to atrazine and dicamba, Persicaria maculosa to atrazine and Digitaria sanguinalis to nicosulfuron. Despite knowledge of these cases, the distribution of these resistant biotypes is unknown. This study aimed to determine the prevalence of known resistant weeds in major maize growing areas in New Zealand, and to pro-actively screen other species for resistance. Weed seeds of broadleaf and grass species were collected from 70 randomly selected maize growing farms in the North Island in 2021-2022. Seeds were grown and treated with herbicides at recommended field rates. Atrazine-resistant C. album were recorded in a third of surveyed farms and nicosulfuron-resistant D. sanguinalis in a sixth. Half of Waikato farms and a quarter of Bay of Plenty farms (no Hawkes Bay or Wellington farms) had atrazine-resistant C. album. Dicamba-resistant C. album were not detected, nor were atrazine-resistant P. maculosa. Nicosulfuron resistant D. sanguinalis was recorded in 19% of Waikato farms, 6% of Bay of Plenty farms and 9% of Hawkes Bay farms (no Wellington farms). Amaranthus spp., Fallopia convolvulus, Persicaria spp., Solanum spp., Echinochloa crus-galli, Panicum spp. and Setaria spp. were not resistant to any of the herbicides tested. Twenty-nine to 52% of maize farms in the North Island are estimated to have herbicide resistant weeds. Resistance is common in maize farms in Waikato and western Bay of Plenty. Resistance is rare in southern regions, with only one instance of nicosulfuron-resistant D. sanguinalis and no resistant C. album. Most annual weeds in maize are not resistant to herbicides; although atrazine resistant C. album is widespread, it is currently controlled with alternative herbicides. Resistant D. sanguinalis appears to be an emerging problem.


Asunto(s)
Atrazina , Herbicidas , Piridinas , Compuestos de Sulfonilurea , Herbicidas/farmacología , Malezas , Zea mays , Dicamba , Nueva Zelanda , Resistencia a los Herbicidas
2.
Clin Ophthalmol ; 18: 269-275, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38312307

RESUMEN

Purpose: To provide a comparative analysis of rates of laser trabeculoplasty (LTP) among eye care providers in the USA. Methods: This retrospective cohort analysis utilized the Centers for Medicare and Medicaid Services (CMS) Public Use File (PUF), 2015-2018. We used CPT code 65855 to select eye care providers who performed LTP in three key US states (KY, LA, and OK). Primary outcomes were eye provider differences in provider count, service count, unique beneficiary count, and Medicare-allowed payments. Asymptotic two-sided chi-squared tests were executed. Statistical significance was achieved at p<0.05. Results: The sum of Medicare-allowed payments for LTP in all three states in 2018 was roughly 26% lower than in 2015. The proportion of Medicare-allowed payments furnished by optometrists increased from 11.3% to 17.9% between 2015 and 2018 (p<0.001). Relative to ophthalmologists, we observed significant increases in optometric Medicare-allowed payments in KY, LA, OK, and the all-inclusive tri-state cohort (all p<0.001). Furthermore, significant optometric increases in number of providers performing LTP (p=0.007), number of unique Medicare beneficiaries seen (p<0.001), and number of LTP services billed (p<0.001) were observed relative to ophthalmologists. Conclusion: The recent expansion of surgical authority by optometrists in key US states is creating a tangible impact on ophthalmologic and optometric practice patterns. The findings of this study may act as provision for policymakers in the context of continually evolving guidelines for optometric surgical expansion.

3.
Neuroimage ; 286: 120515, 2024 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-38216105

RESUMEN

Many sensory brain areas are organized as topographic maps where neural response preferences change gradually across the cortical surface. Within association cortices, 7-Tesla fMRI and neural model-based analyses have also revealed many topographic maps for quantities like numerosity and event timing, often in similar locations. Numerical and temporal quantity estimations also show behavioral similarities and even interactions. For example, the duration of high-numerosity displays is perceived as longer than that of low-numerosity displays. Such interactions are often ascribed to a generalized magnitude system with shared neural responses across quantities. Anterior quantity responses are more closely linked to behavior. Here, we investigate whether common quantity representations hierarchically emerge by asking whether numerosity and timing maps become increasingly closely related in their overlap, response preferences, and topography. While the earliest quantity maps do not overlap, more superior maps overlap increasingly. In these overlapping areas, some intraparietal maps have consistently correlated numerosity and timing preferences, and some maps have consistent angles between the topographic progressions of numerosity and timing preferences. However, neither of these relationships increases hierarchically like the amount of overlap does. Therefore, responses to different quantities are initially derived separately, then progressively brought together, without generally becoming a common representation. Bringing together distinct responses to different quantities may underlie behavioral interactions and allow shared access to comparison and action planning systems.


Asunto(s)
Mapeo Encefálico , Encéfalo , Humanos , Estimulación Luminosa , Imagen por Resonancia Magnética , Corteza Cerebral
5.
Sci Total Environ ; 873: 162293, 2023 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-36813205

RESUMEN

Ocean acidification can severely affect bivalve molluscs, especially their shell calcification. Assessing the fate of this vulnerable group in a rapidly acidifying ocean is therefore a pressing challenge. Volcanic CO2 seeps are natural analogues of future ocean conditions that offer unique insights into the scope of marine bivalves to cope with acidification. Here, we used a 2-month reciprocal transplantation of the coastal mussel Septifer bilocularis collected from reference and elevated pCO2 habitats to explore how they calcify and grow at CO2 seeps on the Pacific coast of Japan. We found significant decreases in condition index (an indication of tissue energy reserves) and shell growth of mussels living under elevated pCO2 conditions. These negative responses in their physiological performance under acidified conditions were closely associated with changes in their food sources (shown by changes to the soft tissue δ13C and δ15N ratios) and changes in their calcifying fluid carbonate chemistry (based on shell carbonate isotopic and elemental signatures). The reduced shell growth rate during the transplantation experiment was further supported by shell δ13C records along their incremental growth layers, as well as their smaller shell size despite being of comparable ontogenetic ages (5-7 years old, based on shell δ18O records). Taken together, these findings demonstrate how ocean acidification at CO2 seeps affects mussel growth and reveal that lowered shell growth helps them survive stressful conditions.


Asunto(s)
Mytilidae , Agua de Mar , Animales , Dióxido de Carbono , Concentración de Iones de Hidrógeno , Acidificación de los Océanos , Carbonatos , Océanos y Mares
6.
Hum Brain Mapp ; 44(5): 2050-2061, 2023 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-36637226

RESUMEN

Perception of dynamic scenes in our environment results from the evaluation of visual features such as the fundamental spatial and temporal frequency components of a moving object. The ratio between these two components represents the object's speed of motion. The human middle temporal cortex hMT+ has a crucial biological role in the direct encoding of object speed. However, the link between hMT+ speed encoding and the spatiotemporal frequency components of a moving object is still under explored. Here, we recorded high resolution 7T blood oxygen level-dependent BOLD responses to different visual motion stimuli as a function of their fundamental spatial and temporal frequency components. We fitted each hMT+ BOLD response with a 2D Gaussian model allowing for two different speed encoding mechanisms: (1) distinct and independent selectivity for the spatial and temporal frequencies of the visual motion stimuli; (2) pure tuning for the speed of motion. We show that both mechanisms occur but in different neuronal groups within hMT+, with the largest subregion of the complex showing separable tuning for the spatial and temporal frequency of the visual stimuli. Both mechanisms were highly reproducible within participants, reconciling single cell recordings from MT in animals that have showed both encoding mechanisms. Our findings confirm that a more complex process is involved in the perception of speed than initially thought and suggest that hMT+ plays a primary role in the evaluation of the spatial features of the moving visual input.


Asunto(s)
Percepción de Movimiento , Animales , Humanos , Percepción de Movimiento/fisiología , Imagen por Resonancia Magnética , Estimulación Luminosa/métodos , Lóbulo Temporal/diagnóstico por imagen , Lóbulo Temporal/fisiología , Neuronas/fisiología
7.
Sci Total Environ ; 865: 161269, 2023 Mar 20.
Artículo en Inglés | MEDLINE | ID: mdl-36587658

RESUMEN

Long-term environmental change, sudden pulses of extreme perturbation, or a combination of both can trigger regime shifts by changing the processes and feedbacks which determine community assembly, structure, and function, altering the state of ecosystems. Our understanding of the mechanisms that stabilise against regime shifts or lock communities into altered states is limited, yet also critical to anticipating future states, preventing regime shifts, and reversing unwanted state change. Ocean acidification contributes to the restructuring and simplification of algal systems, however the mechanisms through which this occurs and whether additional drivers are involved requires further study. Using monthly surveys over three years at a shallow-water volcanic seep we examined how the composition of algal communities change seasonally and following periods of significant physical disturbance by typhoons at three levels of ocean acidification (equivalent to means of contemporary ∼350 and future ∼500 and 900 µatm pCO2). Sites exposed to acidification were increasingly monopolised by structurally simple, fast-growing turf algae, and were clearly different to structurally complex macrophyte-dominated reference sites. The distinct contemporary and acidified community states were stabilised and maintained at their respective sites by different mechanisms following seasonal typhoon disturbance. Macroalgal-dominated sites were resistant to typhoon damage. In contrast, significant losses of algal biomass represented a near total ecosystem reset by typhoons for the turf-dominated communities at the elevated pCO2 sites (i.e. negligible resistance). A combination of disturbance and subsequent turf recovery maintained the same simplified state between years (elevated CO2 levels promote turf growth following algal removal, inhibiting macroalgal recruitment). Thus, ocean acidification may promote shifts in algal systems towards degraded ecosystem states, and short-term disturbances which reset successional trajectories may 'lock-in' these alternative states of low structural and functional diversity.


Asunto(s)
Tormentas Ciclónicas , Ecosistema , Agua de Mar/química , Concentración de Iones de Hidrógeno , Acidificación de los Océanos
8.
Microb Ecol ; 85(4): 1202-1214, 2023 May.
Artículo en Inglés | MEDLINE | ID: mdl-35378620

RESUMEN

Plastics are accumulating in the world's oceans, while ocean waters are becoming acidified by increased CO2. We compared metagenome of biofilms on tethered plastic bottles in subtidal waters off Japan naturally enriched in CO2, compared to normal ambient CO2 levels. Extending from an earlier amplicon study of bacteria, we used metagenomics to provide direct insights into changes in the full range of functional genes and the entire taxonomic tree of life in the context of the changing plastisphere. We found changes in the taxonomic community composition of all branches of life. This included a large increase in diatom relative abundance across the treatments but a decrease in diatom diversity. Network complexity among families decreased with acidification, showing overall simplification of biofilm integration. With acidification, there was decreased prevalence of genes associated with cell-cell interactions and antibiotic resistance, decreased detoxification genes, and increased stress tolerance genes. There were few nutrient cycling gene changes, suggesting that the role of plastisphere biofilms in nutrient processes within an acidified ocean may not change greatly. Our results suggest that as ocean CO2 increases, the plastisphere will undergo broad-ranging changes in both functional and taxonomic composition, especially the ecologically important diatom group, with possible wider implications for ocean ecology.


Asunto(s)
Diatomeas , Agua de Mar , Humanos , Plásticos , Concentración de Iones de Hidrógeno , Acidificación de los Océanos , Dióxido de Carbono , Biopelículas , Diatomeas/genética
9.
Mar Pollut Bull ; 182: 113954, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35914433

RESUMEN

Coral diseases contribute to the rapid degradation of coral reefs on a global scale. Although widespread in tropical and subtropical reefs, disease outbreaks have not been described in warm temperate areas. Here, we report the outbreak of a new coral disease in a warm temperate marginal coral community in Japan. Outbreaks of the disease have been observed during the summer and autumn months since 2014. It affects the coral species Porites heronensis and was tentatively named "White Mat Syndrome" (WMS) as it consists of a white microbial mat dominated by Thiothrix sp., a sulfide oxidizing bacteria. Outbreaks followed high seasonal temperatures and were associated with the macroalga Gelidium elegans, which acts as a pathogen reservoir. With ocean warming and the anticipated increase in novel coral-algae interactions as some coral species shift poleward, WMS and emerging diseases could hinder the role of temperate areas as a future coral refuge.


Asunto(s)
Antozoos , Animales , Antozoos/microbiología , Arrecifes de Coral , Brotes de Enfermedades , Calor , Estaciones del Año
10.
Nat Commun ; 13(1): 3952, 2022 07 08.
Artículo en Inglés | MEDLINE | ID: mdl-35804026

RESUMEN

Quantifying the timing (duration and frequency) of brief visual events is vital to human perception, multisensory integration and action planning. Tuned neural responses to visual event timing have been found in association cortices, in areas implicated in these processes. Here we ask how these timing-tuned responses are related to the responses of early visual cortex, which monotonically increase with event duration and frequency. Using 7-Tesla functional magnetic resonance imaging and neural model-based analyses, we find a gradual transition from monotonically increasing to timing-tuned neural responses beginning in the medial temporal area (MT/V5). Therefore, across successive stages of visual processing, timing-tuned response components gradually become dominant over inherent sensory response modulation by event timing. This additional timing-tuned response component is independent of retinotopic location. We propose that this hierarchical emergence of timing-tuned responses from sensory processing areas quantifies sensory event timing while abstracting temporal representations from spatial properties of their inputs.


Asunto(s)
Corteza Visual , Percepción Visual , Mapeo Encefálico , Corteza Cerebral/fisiología , Humanos , Imagen por Resonancia Magnética , Estimulación Luminosa , Sensación , Corteza Visual/diagnóstico por imagen , Corteza Visual/fisiología , Percepción Visual/fisiología
11.
Am J Ophthalmol Case Rep ; 27: 101610, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35756838

RESUMEN

Purpose: To report treatment of uncontrolled intraocular pressure in a patient with uveal melanoma status post plaque radiotherapy with ab interno XEN gel stent implantation. Observations: A 21-year-old female with a history of iris and ciliary body melanoma underwent treatment with plaque radiotherapy with subsequent elevation of intraocular pressure refractory to maximum medical therapy. In order to control the pressure, ab interno XEN gel stent implantation with mitomycin C was recommended. Preoperatively, the patient was on four topical medications and oral acetazolamide with intraocular pressure of 39 mmHg by Goldmann applanation tonometry. The patient's intraocular pressure was reduced to 10 mmHg at her final postoperative visit on no medications. Visual acuity showed minimal degradation measuring 20/100 preoperatively and 20/150 eleven months after XEN gel stent implantation with VA improvement to 20/60 with refraction after cataract extraction at eighteen months. There were no postoperative complications and no recurrence or seeding of the uveal melanoma at follow up 18 months after her XEN gel stent implantation. Conclusions and Importance: Ab interno XEN gel stent implantation with mitomycin C may offer an effective method to control intraocular pressure in patients with refractory intraoperative pressure control following plaque radiotherapy treatment for uveal melanoma.

12.
Cell Rep ; 39(13): 111005, 2022 06 28.
Artículo en Inglés | MEDLINE | ID: mdl-35767956

RESUMEN

Numerosity, the set size of a group of items, helps guide behavior and decisions. Previous studies have shown that neural populations respond selectively to numerosities. How numerosity is extracted from the visual scene is a longstanding debate, often contrasting low-level visual with high-level cognitive processes. Here, we investigate how attention influences numerosity-selective responses. The stimuli consisted of black and white dots within the same display. Participants' attention was focused on either black or white dots, while we systematically changed the numerosity of black, white, and total dots. Using 7 T fMRI, we show that the numerosity-tuned neural populations respond only when attention is focused on their preferred numerosity, irrespective of the unattended or total numerosities. Without attention, responses to preferred numerosity are suppressed. Unlike traditional effects of attention in the visual cortex, where attention enhances already existing responses, these results suggest that attention is required to drive numerosity-selective responses.


Asunto(s)
Atención , Imagen por Resonancia Magnética , Atención/fisiología , Humanos , Imagen por Resonancia Magnética/métodos
13.
Neuroimage ; 258: 119366, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35690255

RESUMEN

Perception of sub-second auditory event timing supports multisensory integration, and speech and music perception and production. Neural populations tuned for the timing (duration and rate) of visual events were recently described in several human extrastriate visual areas. Here we ask whether the brain also contains neural populations tuned for auditory event timing, and whether these are shared with visual timing. Using 7T fMRI, we measured responses to white noise bursts of changing duration and rate. We analyzed these responses using neural response models describing different parametric relationships between event timing and neural response amplitude. This revealed auditory timing-tuned responses in the primary auditory cortex, and auditory association areas of the belt, parabelt and premotor cortex. While these areas also showed tonotopic tuning for auditory pitch, pitch and timing preferences were not consistently correlated. Auditory timing-tuned response functions differed between these areas, though without clear hierarchical integration of responses. The similarity of auditory and visual timing tuned responses, together with the lack of overlap between the areas showing these responses for each modality, suggests modality-specific responses to event timing are computed similarly but from different sensory inputs, and then transformed differently to suit the needs of each modality.


Asunto(s)
Corteza Auditiva , Música , Estimulación Acústica , Corteza Auditiva/fisiología , Percepción Auditiva/fisiología , Mapeo Encefálico , Humanos , Imagen por Resonancia Magnética
14.
Nat Commun ; 13(1): 1340, 2022 03 15.
Artículo en Inglés | MEDLINE | ID: mdl-35292648

RESUMEN

Human early visual cortex response amplitudes monotonically increase with numerosity (object number), regardless of object size and spacing. However, numerosity is typically considered a high-level visual or cognitive feature, while early visual responses follow image contrast in the spatial frequency domain. We find that, at fixed contrast, aggregate Fourier power (at all orientations and spatial frequencies) follows numerosity closely but nonlinearly with little effect of object size, spacing or shape. This would allow straightforward numerosity estimation from spatial frequency domain image representations. Using 7T fMRI, we show monotonic responses originate in primary visual cortex (V1) at the stimulus's retinotopic location. Responses here and in neural network models follow aggregate Fourier power more closely than numerosity. Truly numerosity tuned responses emerge after lateral occipital cortex and are independent of retinotopic location. We propose numerosity's straightforward perception and neural responses may result from the pervasive spatial frequency analyses of early visual processing.


Asunto(s)
Corteza Visual , Percepción Visual , Mapeo Encefálico/métodos , Cognición , Humanos , Imagen por Resonancia Magnética/métodos , Lóbulo Occipital , Estimulación Luminosa , Corteza Visual/diagnóstico por imagen , Corteza Visual/fisiología , Percepción Visual/fisiología
15.
Nat Commun ; 13(1): 1148, 2022 03 03.
Artículo en Inglés | MEDLINE | ID: mdl-35241666

RESUMEN

The Eurasian subtropical westerly jet (ESWJ) is a major feature of the summertime atmospheric circulation in the Northern Hemisphere. Here, we demonstrate a robust weakening trend in the summer ESWJ over the last four decades, linked to significant impacts on extreme weather. Analysis of climate model simulations from the Coupled Model Intercomparison Project Phase 6 (CMIP6) suggests that anthropogenic aerosols were likely the primary driver of the weakening ESWJ. Warming over mid-high latitudes due to aerosol reductions in Europe, and cooling in the tropics and subtropics due to aerosol increases over South and East Asia acted to reduce the meridional temperature gradient at the surface and in the lower and middle troposphere, leading to reduced vertical shear of the zonal wind and a weaker ESWJ in the upper troposphere. If, as expected, Asian anthropogenic aerosol precursor emissions decline in future, our results imply a renewed strengthening of the summer ESWJ.


Asunto(s)
Viento , Aerosoles/análisis , Europa (Continente) , Estaciones del Año , Temperatura
16.
Zoolog Sci ; 39(1): 41-51, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-35106992

RESUMEN

Japan has many coastal carbon dioxide seeps as it is one of the most volcanically active parts of the world. These shallow seeps do not have the spectacular aggregations of specialist fauna seen in deep-sea vent systems but they do have gradients in seawater carbonate chemistry that are useful as natural analogues of the effects of ocean acidification on marine biodiversity, ecosystem function and fisheries. Here, we compare macroinvertebrate diversity and abundance on rocky habitats at ambient (mean ≤ 410 µatm) and high (mean 971-1484 µatm) levels of seawater pCO2 in the warm-temperate region of Japan, avoiding areas with toxic sulphur or warm-water conditions. We show that although 70% of intertidal taxa and 40% of shallow subtidal taxa were able to tolerate the high CO2 conditions, there was a marked reduction in the abundance of corals, bivalves and gastropods in acidified conditions. A narrower range of filter feeders, grazers, detritivores, scavengers and carnivores were present at high CO2 resulting in a simplified coastal system that was unable to retain the high standing stocks of marine carbon biomass found in ambient conditions. It is clear that cuts in CO2 emissions would reduce the risks of climate change and ocean acidification impacts on marine biodiversity, shellfish production and biomass in the rocky coastal shores of this region.


Asunto(s)
Ecosistema , Agua de Mar , Animales , Dióxido de Carbono/análisis , Concentración de Iones de Hidrógeno , Invertebrados , Japón
17.
Glob Chang Biol ; 28(2): 362-374, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34689395

RESUMEN

Ocean acidification (OA) is a major threat to the persistence of biogenic reefs throughout the world's ocean. Coralline algae are comprised of high magnesium calcite and have long been considered one of the most susceptible taxa to the negative impacts of OA. We summarize these impacts and explore the causes of variability in coralline algal responses using a review/qualitative assessment of all relevant literature, meta-analysis, quantitative assessment of critical responses, and a discussion of physiological mechanisms and directions for future research. We find that most coralline algae experienced reduced abundance, calcification rates, recruitment rates, and declines in pH within the site of calcification in laboratory experiments simulating OA or at naturally elevated CO2 sites. There were no other consistent physiological responses of coralline algae to simulated OA (e.g., photo-physiology, mineralogy, and survival). Calcification/growth was the most frequently measured parameters in coralline algal OA research, and our meta-analyses revealed greater declines in seawater pH were associated with significant decreases in calcification in adults and similar but nonsignificant trends for juveniles. Adults from the family Mesophyllumaceae also tended to be more robust to OA, though there was insufficient data to test similar trends for juveniles. OA was the dominant driver in the majority of laboratory experiments where other local or global drivers were assessed. The interaction between OA and any other single driver was often additive, though factors that changed pH at the surface of coralline algae (light, water motion, epiphytes) acted antagonistically or synergistically with OA more than any other drivers. With advances in experimental design and methodological techniques, we now understand that the physiology of coralline algal calcification largely dictates their responses to OA. However, significant challenges still remain, including improving the geographic and life-history spread of research effort and a need for holistic assessments of physiology.


Asunto(s)
Rhodophyta , Agua de Mar , Calcificación Fisiológica , Concentración de Iones de Hidrógeno , Océanos y Mares
18.
Trends Cogn Sci ; 26(1): 11-24, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34702662

RESUMEN

Perception of quantities, such as numerosity, timing, and size, is essential for behavior and cognition. Accumulating evidence demonstrates neurons processing quantities are tuned, that is, have a preferred quantity amount, not only for numerosity, but also other quantity dimensions and sensory modalities. We argue that quantity-tuned neurons are fundamental to understanding quantity perception. We illustrate how the properties of quantity-tuned neurons can underlie a range of perceptual phenomena. Furthermore, quantity-tuned neurons are organized in distinct but overlapping topographic maps. We suggest that this overlap in tuning provides the neural basis for perceptual interactions between different quantities, without the need for a common neural representational code.


Asunto(s)
Neuronas , Percepción , Humanos , Estimulación Luminosa/métodos
19.
Trends Ecol Evol ; 37(1): 20-29, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34593256

RESUMEN

Marine heatwaves (MHWs), discrete but prolonged periods of anomalously warm seawater, can fundamentally restructure marine communities and ecosystems. Although our understanding of these events has improved in recent years, key knowledge gaps hinder our ability to predict how MHWs will affect patterns of biodiversity. Here, we outline a functional trait approach that enables a better understanding of which species and communities will be most vulnerable to MHWs, and how the distribution of species and composition of communities are likely to shift through time. Our perspective allows progress toward unifying extreme events and longer term environmental trends as co-drivers of ecological change, with the incorporation of species traits into our predictions allowing for a greater capacity to make management decisions.


Asunto(s)
Biodiversidad , Ecosistema , Cambio Climático , Fenotipo
20.
Brain Struct Funct ; 226(9): 2839-2853, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34245381

RESUMEN

Healthy human aging is associated with a deterioration of visual acuity, retinal thinning, visual field map shrinkage and increasing population receptive field sizes. Here we ask how these changes are related to each other in a cross-sectional sample of fifty healthy adults aged 20-80 years. We hypothesized that age-related loss of macular retinal ganglion cells may lead to decreased visual field map sizes, and both may lead to increased pRF sizes in the cortical central visual field representation. We measured our participants' perceptual corrected visual acuity using standard ophthalmological letter charts. We then measured their early visual field map (V1, V2 and V3) functional population receptive field (pRF) sizes and structural surface areas using fMRI, and their retinal structure using high-definition optical coherence tomography. With increasing age visual acuity decreased, pRF sizes increased, visual field maps surface areas (but not whole-brain surface areas) decreased, and retinal thickness decreased. Among these measures, only functional pRF sizes predicted perceptual visual acuity, and Bayesian statistics support a null relationship between visual acuity and cortical or retinal structure. However, pRF sizes were in turn predicted by cortical structure only (visual field map surface areas), which were only predicted by retinal structure (thickness). These results suggest that simultaneous disruptions of neural structure and function throughout the early visual system may underlie the deterioration of perceptual visual acuity in healthy aging.


Asunto(s)
Envejecimiento Saludable , Retina , Corteza Visual , Teorema de Bayes , Mapeo Encefálico , Estudios Transversales , Humanos , Imagen por Resonancia Magnética , Retina/anatomía & histología , Agudeza Visual , Corteza Visual/diagnóstico por imagen , Campos Visuales
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