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Long-term satellite observations show continuous increase of vegetation growth enhancement in urban environment
Get PDFUrbanization shows continuous expansion and development, ushering in the co-evolution of urban environments and vegetation over time. Recent remote sensing-based studies have discovered prevalent vegetation growth enhancement in urban environments. However, whether there is a temporal evolution of the growth enhancement remains unknown and unexplored. Here we expanded the existing framework for assessing the long-term impact of urbanization on vegetation greenness (enhanced vegetation index, EVI) using long time series of remote sensing images and applied it in Changsha, the capital city of Hunan province in China. Results showed that vegetation growth experienced widespread enhancement from 2000 to 2017, and increased 1.8 times from 2000 to 2017, suggesting strong continuous adaptive capability of vegetation to urban conditions. Although the overall impact of urbanization was negative due to the replacement of vegetated surfaces, the growth enhancement nevertheless offset or compensated the direct loss of vegetated cover during urbanization in the magnitude of 28% in 2000 to 44% in 2017. Our study also revealed large spatial heterogeneity in vegetation growth response among various districts at different urbanization levels and found an emergent trend under the observed spatial heterogeneity toward an asymptotic maximum with urbanization, showing EVI converges to 0.22 in highly urbanized areas. We further found that the positive effect of urbanization on vegetation growth is a function of urbanization intensity and time, which implies that the effect of the urban environment on vegetation can be simulated and predicted, and can be verified in more cities in the future. Our study is the first to successfully quantify long-term spatial patterns on the co-evolution of urbanization and vegetation, providing a new understanding of the continuous adaptive responses of vegetation growth to urbanization and shedding light on predicting 24 biological responses to future environmental change
Top ten priorities for global saltmarsh restoration, conservation and ecosystem service research
Get PDFCoastal saltmarshes provide globally important ecosystem services including ‘blue carbon’ sequestration, flood protection, pollutant remediation, habitat provision and cultural value. Large portions of marshes have been lost or fragmented as a result of land reclamation, embankment construction, and pollution. Sea level rise threatens marsh survival by blocking landward migration where coastlines have been developed. Research-informed saltmarsh conservation and restoration efforts are helping to prevent further loss, yet significant knowledge gaps remain. Using a mixed methods approach, this paper identifies ten research priorities through an online questionnaire and a residential workshop attended by an international, multi-disciplinary network of 35 saltmarsh experts spanning natural, physical and social sciences across research, policy, and practitioner sectors. Priorities have been grouped under four thematic areas of research: Saltmarsh Area Extent, Change and Restoration Potential (including past, present, global variation), Spatio-social contexts of Ecosystem Service delivery (e.g. influences of environmental context, climate change, and stakeholder groups on service provisioning), Patterns and Processes in saltmarsh functioning (global drivers of saltmarsh ecosystem structure/function) and Management and Policy Needs (how management varies contextually; challenges/opportunities for management). Although not intended to be exhaustive, the challenges, opportunities, and strategies for addressing each research priority examined here, providing a blueprint of the work that needs to be done to protect saltmarshes for future generations
Macroalgae exhibit diverse responses to human disturbances on coral reefs
Get PDFScientists and managers rely on indicator taxa such as coral and macroalgal cover to evaluate the effects of human disturbance on coral reefs, often assuming a universally positive relationship between local human disturbance and macroalgae. Despite evidence that macroalgae respond to local stressors in diverse ways, there have been few efforts to evaluate relationships betweenspecific macroalgae taxa and local human-driven disturbance. Using genus-level monitoring data from 1,205 sites in the Indian and Pacific Oceans, we assess whether macroalgae percent cover correlates with local human disturbance while accounting for factors that could obscure or confound relationships. Assessing macroalgae at genus level revealed that no genera were positively correlated with all human disturbance metrics. Instead, we found relationshipsbetween the division or genera of algae and specific human disturbances that were not detectable when pooling taxa into a single functional category, which is common to many analyses. The convention to use percent cover of macroalgae as an indication of local human disturbance therefore likely obscures signatures of local anthropogenic threats to reefs. Our limited understanding of relationships between human disturbance, macroalgae taxa, and their responsesto human disturbances impedes the ability to diagnose and respond appropriately to these threats
Completely non-invasive cell manipulation in lens-integrated microfluidic devices by single-fiber optical tweezers
Get PDFIn a fiber-based optical tweezer system, it is a common practice to insert the fiber probe into the sample solution to perform the tweezer function. Such a configuration of the fiber probe may lead to unwanted contamination and/or damage to the sample system and is thus potentially invasive. Here, we propose a completely non-invasive method for cell manipulation by combining a microcapillary microfluidic device and an optical fiber tweezer. We demonstrate that Chlorella cells inside the microcapillary channel can be successfully trapped and manipulated by an optical fiber probe located outside of the microcapillary, thus making the process completely non-invasive. The fiber does not even invade the sample solution. To our knowledge, this is the first report of such a method. The speed of stable manipulation can reach the 7 µm/s scale. We found that the curved walls of the microcapillaries worked like a lens, which helped to boost the light focusing and trapping efficiency. Numerical simulation of optical forces under medium settings reveals that the optical forces can be enhanced by up to 1.44 times, and the optical forces can change direction under certain conditions
Wide-Field and Real-Time Super-Resolution Optical Imaging By Titanium Dioxide Nanoparticle-Assembled Solid Immersion Lens
Get PDFSuper-resolution optical imaging techniques can break the optical diffraction limit, thus providing unique opportunities to visualize the microscopic world at the nanoscale. Although near-field optical microscopy techniques have been proven to achieve significantly improved imaging resolution, most near-field approaches still suffer from a narrow field of view (FOV) or difficulty in obtaining wide-field images in real time, which may limit their widespread and diverse applications. Here, the authors experimentally demonstrate an optical microscope magnification and image enhancement approach by using a submillimeter-sized solid immersion lens (SIL) assembled by densely-packed 15 nm TiO2 nanoparticles through a silicone oil two-step dehydration method. This TiO2 nanoparticle-assembled SIL can achieve both high transparency and high refractive index, as well as sufficient mechanical strength and easy-to-handle size, thus providing a fast, wide-field, real-time, non-destructive, and low-cost solution for improving the quality of optical microscopic observation of a variety of samples, including nanomaterials, cancer cells, and living cells or bacteria under conventional optical microscopes. This study provides an attractive alternative to simplify the fabrication and applications of high-performance SILs
The fate of amino acid and peptide as affected by soil depth and fertilization regime in subtropical paddies
Get PDFAmino acids and peptides are important regulators of ecosystem functioning due to their potential role as direct nutrient sources for plants and soil microbes. However, the turnover and driving factors of these compounds in agricultural soils remain poorly understood. This study aimed to reveal the short-term fate of C-labeled alanine and tri-alanine derived C under flooding conditions of the top (0-20 cm) and sub-horizons (20-40 cm) of subtropical paddy soils taken from four long-term (31 years since treatment) nitrogen (N) fertilization regimes (i.e., without fertilization, NPK, NPK with straw return (NPKS) or with manure (NPKM)). Amino acid mineralization was strongly affected by the N fertilization regime and soil depth, while peptide mineralization was only distinct between soil layers. The average half-life of amino acid and peptide in the topsoil was 8 h across all treatments, which was higher than previously reported in uplands. The microbial turnover of amino acid and peptide was 7-10 times slower in the subsoil than in the topsoil, with a half-life of about 2-3 days. The half-life of amino acid and peptide for the respired pool was strongly associated with soil physicochemical characteristics, the total biomass, and the structure of soil microbial communities. The N fertilization regime and soil depth affected the substrate uptake rate by microorganisms, with greater uptake observed in the NPKS and NPKM treatments and the topsoil. Microbial amino acid uptake was correlated with the biomass of total and individual microbial groups, whereas microbial peptide uptake was associated with the soil microbial community structure and physicochemical characteristics. This suggests that there are various pathways of amino acid and peptide use by microorganisms under flooding conditions. We conclude that microbial mineralization of amino acid and its peptide in paddy soils under flooding conditions is slower than in upland soils, and that microbial uptake of these substrates is related to soil abiotic factors and the biomass and structure of soil microbial community. These findings have important implications for understanding nutrient cycling and ecosystem functioning in agricultural soils. [Abstract copyright: Copyright © 2023 Elsevier B.V. All rights reserved.
RCT-based Social Return on Investment (SROI) of a home exercise programme for people with early dementia comparing in-person and blended delivery before and during the COVID-19 pandemic
Get PDFBackground Regular exercise and community engagement may slow the rate of function loss for people with dementia. However, the evidence is uncertain regarding the cost-effectiveness and social return on investment (SROI) of home exercise with community referral for people with dementia. This study aimed to compare the social value generated from the in-person PrAISED programme delivered before March 2020 with a blended PrAISED programme delivered after March 2020.Methods SROI analysis was conducted alongside a randomised controlled trial (RCT). Of 205 patient participants and their carers who completed cost data, 61 completed an in-person programme before March 2020. Due to COVID-19 pandemic restrictions, 144 patient participants completed a blended programme consisting of a combination of in-person visits, phone calls and video conferencing with multidisciplinary team (MDT) members.SROI analysis compared in-person and blended delivery formats. Five relevant and material outcomes were identified: three outcomes for patient participants (fear of falling, health-related quality of life, and social connection); one outcome for carer participants (carer strain index), and one outcome for the NHS (health service resource use). Data were collected at baseline and a 12-month follow-up.Results The in-person PrAISED programme generated SROI ratios ranging from £0.58 to £2.33 for every £1 invested. In-person PrAISED patient participants gained social value from improved health-related quality of life, social connection, and less fear of falling. In-person PrAISED carer participants acquired social value from less carer strain. The NHS gained benefit from less health care service resource use. However, the blended PrAISED programme generated lower SROI ratios ranging from a negative ratio to £0.08: £1.Conclusion Compared with the blended programme, the PrAISED in-person programme generated higher SROI ratios for people with early dementia. During the COVID-19 pandemic and its restrictions, a blended delivery of the programme and the curtailment of community activities resulted in lower SROI ratios during this period. An in-person PrAISED intervention with community referral is likely to provide better value for money than a blended one with limited community referral, despite the greater costs of the former
A record-breaking extreme heat event caused unprecedented warming of lakes in China
Get PDFStrong evidence confirms that extreme climatic events, such as heat waves, storms and droughts, are becoming more frequent due to anthropogenic climate change [1]. These extreme events may have overwhelmingly negative impacts on lake ecosystems [2]. Specifically, by warming lake surface waters, extreme heat events are expected to influence many within-lake physical, chemical and biological processes [3]. Critically, extreme heat events can alter the lake environment in only a fraction of the time that is needed for achieving the same effect of long-term climate change [4]. In some cases, extreme heat events can exceed the resilience capacity of a lake ecosystem and lead to a loss of functionality and can even trigger catastrophic regime shifts [5]. From mid-June to late August 2022, a record-breaking extreme heat event, with the longest duration and highest intensity since recording began in 1961, swept across China [6]. The direct driver of this heat event was the Western Pacific Subtropical High, which normally sits as a smaller pressure system to the east of Yangtze River Basin. However, in summer 2022, the system was strong and hovered over Yangtze River Basin, thereby preventing cold air from the north and moisture from the Indian Ocean from reaching the region [6]. Here, we used satellite observations from 2000 to 2022 to demonstrate the effects of the unprecedented warming of China’s lakes caused by this extreme event
Investigating the impact of the pandemic on children’s, teacher’s and parent’s health and wellbeing in SEN contexts.
Get PDFCross-validation for geospatial data: Estimating generalization performance in geostatistical problems
Get PDFGeostatistical learning problems are frequently characterized by spatial autocorrelation in the input features and/or the potential for covariate shift at test time. These realities violate the classical assumption of independent, identically distributed data, upon which most cross-validation algorithms rely in order to estimate the generalization performance of a model. In this paper, we present a theoretical criterion for unbiased cross-validation estimators in the geospatial setting. We also introduce a new cross-validation algorithm toevaluate models, inspired by the challenges of geospatial problems. We apply a framework for categorizing problems into different types of geospatial scenarios to help practitioners select an appropriate cross-validation strategy. Our empirical analyses compare cross-validation algorithms on both simulated and several real datasets to develop recommendations for a variety of geospatial settings. This paper aims to draw attention to some challenges that arise in model evaluation for geospatial problems and to provide guidance for users