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  1. Article ; Online: Spatial and Ecological Scaling of Stability in Spatial Community Networks

    Javier Jarillo / Francisco J. Cao-García / Frederik De Laender

    Frontiers in Ecology and Evolution, Vol

    2022  Volume 10

    Abstract: There are many scales at which to quantify stability in spatial and ecological networks. Local-scale analyses focus on specific nodes of the spatial network, while regional-scale analyses consider the whole network. Similarly, species- and community- ... ...

    Abstract There are many scales at which to quantify stability in spatial and ecological networks. Local-scale analyses focus on specific nodes of the spatial network, while regional-scale analyses consider the whole network. Similarly, species- and community-level analyses either account for single species or for the whole community. Furthermore, stability itself can be defined in multiple ways, including resistance (the inverse of the relative displacement caused by a perturbation), initial resilience (the rate of return after a perturbation), and invariability (the inverse of the relative amplitude of the population fluctuations). Here, we analyze the scale-dependence of these stability properties. More specifically, we ask how spatial scale (local vs. regional) and ecological scale (species vs. community) influence these stability properties. We find that regional initial resilience is the weighted arithmetic mean of the local initial resiliences. The regional resistance is the harmonic mean of local resistances, which makes regional resistance particularly vulnerable to nodes with low stability, unlike regional initial resilience. Analogous results hold for the relationship between community- and species-level initial resilience and resistance. Both resistance and initial resilience are “scale-free” properties: regional and community values are simply the biomass-weighted means of the local and species values, respectively. Thus, one can easily estimate both stability metrics of whole networks from partial sampling. In contrast, invariability generally is greater at the regional and community-level than at the local and species-level, respectively. Hence, estimating the invariability of spatial or ecological networks from measurements at the local or species level is more complicated, requiring an unbiased estimate of the network (i.e., region or community) size. In conclusion, we find that scaling of stability depends on the metric considered, and we present a reliable framework to estimate these metrics.
    Keywords scale ; stability ; resistance ; invariability ; regional ; community ; Evolution ; QH359-425 ; Ecology ; QH540-549.5
    Subject code 333
    Language English
    Publishing date 2022-06-01T00:00:00Z
    Publisher Frontiers Media S.A.
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: Enhanced summertime ozone and SOA from biogenic volatile organic compound (BVOC) emissions due to vegetation biomass variability during 1981–2018 in China

    J. Cao / S. Situ / Y. Hao / S. Xie / L. Li

    Atmospheric Chemistry and Physics, Vol 22, Pp 2351-

    2022  Volume 2364

    Abstract: Coordinated control of fine particulate matter (PM 2.5 ) and ozone (O 3 ) has become a new and urgent issue for China's air pollution control. Biogenic volatile organic compounds (BVOCs) are important precursors of O 3 and secondary organic aerosol (SOA) ...

    Abstract Coordinated control of fine particulate matter (PM 2.5 ) and ozone (O 3 ) has become a new and urgent issue for China's air pollution control. Biogenic volatile organic compounds (BVOCs) are important precursors of O 3 and secondary organic aerosol (SOA) formation. China experienced a rapid increase in BVOC emissions as a result of increased vegetation biomass. We applied WRF-Chem3.8 coupling with MEGAN2.1 to conduct long-term simulations for impacts of BVOC emissions on O 3 and SOA during 1981–2018, using the emission factors extrapolated by localized emission rates and annual vegetation biomass. In summer 2018, BVOC emissions were 9.91 Tg (in June), which led to an average increase of 8.6 ppb (16.75 % of the total) in daily maximum 8 h (MDA8) O 3 concentration and 0.84 µg m −3 (73.15 % of the total) in SOA over China. The highest contribution to O 3 is concentrated in the Great Khingan Mountains, Qinling Mountains, and most southern regions while in southern areas for SOA. Isoprene has the greatest contribution to O 3 , while monoterpene has the largest SOA production. BVOC emissions have distinguished impacts in different regions. The Chengdu–Chongqing (CC) region has the highest O 3 and SOA generated by BVOCs, while the Beijing–Tianjin–Hebei (BTH) region has the lowest. From 1981 to 2018, the interannual variation of BVOC emissions caused by increasing leaf biomass resulted in O 3 concentration increasing by 7.38 % at an average rate of 0.11 ppb yr −1 and SOA increasing by 39.30 % at an average rate of 0.008 µg m −3 yr −1 . Due to the different changing trends of leaf biomass by region and vegetation type, O 3 and SOA show different interannual variations. The Fenwei Plain (FWP), Yangtze River Delta (YRD), and Pearl River Delta (PRD) regions have the most rapid O 3 increment, while the increasing rate of SOA in CC is the highest. BTH has the smallest enhancement in O 3 and SOA concentration. This study will help to recognize the impact of historical BVOC emissions on O 3 and SOA and further provide a ...
    Keywords Physics ; QC1-999 ; Chemistry ; QD1-999
    Subject code 511 ; 333
    Language English
    Publishing date 2022-02-01T00:00:00Z
    Publisher Copernicus Publications
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article ; Online: Impacts of biomass burning and photochemical processing on the light absorption of brown carbon in the southeastern Tibetan Plateau

    J. Tian / Q. Wang / Y. Ma / J. Wang / Y. Han / J. Cao

    Atmospheric Chemistry and Physics, Vol 23, Pp 1879-

    2023  Volume 1892

    Abstract: Brown carbon (BrC) in the atmosphere can greatly influence aerosol's radiative forcing over the Tibetan Plateau (TP) because it has the non-negligible capacity of light absorption compared to black carbon (BC); however, our understanding of optical ... ...

    Abstract Brown carbon (BrC) in the atmosphere can greatly influence aerosol's radiative forcing over the Tibetan Plateau (TP) because it has the non-negligible capacity of light absorption compared to black carbon (BC); however, our understanding of optical properties, sources, and atmospheric processes of BrC in this region remains limited. In this study, a multiple-wavelength Aethalometer coupled with a quadrupole aerosol chemical speciation monitor was deployed to investigate the highly time resolved BrC in the submicron aerosol at the southeastern edge of the TP during the pre-monsoon season. The results showed that BrC made substantial contributions (20.0 %–40.2 %) to the light absorption of submicron aerosol from 370 to 660 nm. Organic aerosol (OA), an alternative to BrC, was split into a biomass burning OA (BBOA) with aging processes and a photochemical-oxidation-processed oxygenated OA (po-OOA) by a hybrid environmental receptor model analysis. Combined with the light absorption coefficient of BrC ( b abs-BrC ), the source-specific mass absorption cross sections of BBOA (0.61–2.78 m 2 g −1 ) and po-OOA (0.30–1.43 m 2 g −1 ) at 370–660 nm were retrieved. On average, b abs-BrC from po-OOA (1.3–6.0 Mm −1 ) was comparable to that from BBOA (1.3–6.0 Mm −1 ) at all wavelengths. The concentration-weighted trajectory analysis showed that the most important potential source regions for b abs-BrC values from BBOA and po-OOA were located in northern Myanmar and along the China–Myanmar border, indicating the cross-border transport of BrC from Southeast Asia. A “simple forcing efficiency” evaluation further illustrated the importance of the BrC radiative effect with the high fractional radiative forcing by two OAs relative to BC (48.8 ± 15.5 %). This study highlights a significant influence of BrC of biomass burning origin and secondary formation on climate change over the TP region during the pre-monsoon season.
    Keywords Physics ; QC1-999 ; Chemistry ; QD1-999
    Subject code 333
    Language English
    Publishing date 2023-02-01T00:00:00Z
    Publisher Copernicus Publications
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article ; Online: Ice formation on lake surfaces in winter causes warm-season bias of lacustrine brGDGT temperature estimates

    J. Cao / Z. Rao / F. Shi / G. Jia

    Biogeosciences, Vol 17, Pp 2521-

    2020  Volume 2536

    Abstract: It has been frequently found that lacustrine branched glycerol dialkyl glycerol tetraethers (brGDGT)-derived temperatures are warm-season-biased relative to measured mean annual air temperature (AT) in the middle to high latitudes, the mechanism of which, ...

    Abstract It has been frequently found that lacustrine branched glycerol dialkyl glycerol tetraethers (brGDGT)-derived temperatures are warm-season-biased relative to measured mean annual air temperature (AT) in the middle to high latitudes, the mechanism of which, however, is not very clear. Here, we investigated the brGDGTs from catchment soils, suspended particulate matter (SPM) and surface sediments in different water depths in Gonghai Lake in northern China to explore this question. Our results showed that the brGDGT distribution in sediments resembled that in the SPM but differed from the surrounding soils, suggesting a substantial aquatic origin of the brGDGTs in the lake. Moreover, the increase in brGDGT content and decrease in methylation index with water depth in sediments suggested more contribution of aquatic brGDGTs produced from deep or bottom waters. Therefore, established lake-specific calibrations were applied to estimate local mean annual AT. As usual, the estimates were significantly higher than the measured mean annual AT. However, they were similar to (and thus actually reflected) the mean annual lake water temperature (LWT). Interestingly, the mean annual LWT is close to the measured mean warm-season AT, thus suggesting that the apparent warm-season bias of lacustrine brGDGT-derived temperatures could be caused by the discrepancy between AT and LWT. In our study region, ice forms at the lake surface during winter, leading to isolation of the underlying lake water from air and hence higher LWT than AT, while LWT basically follows AT during warm seasons when ice disappears. Therefore, we think that lacustrine brGDGTs actually reflected the mean annual LWT, which is higher than the mean annual AT in our study location. Since the decoupling between LWT and AT in winter due to ice formation is a universal physical phenomenon in the middle to high latitudes, we propose this phenomenon could be also the reason for the widely observed warm-season bias of brGDGT-derived temperatures in other seasonally surface ice-forming lakes, especially in shallow lakes.
    Keywords Ecology ; QH540-549.5 ; Life ; QH501-531 ; Geology ; QE1-996.5
    Subject code 550
    Language English
    Publishing date 2020-05-01T00:00:00Z
    Publisher Copernicus Publications
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  5. Article ; Online: The nonshivering thermogenesis of brown adipose tissue and fat mobilization of striped hamsters exposed to cycles of cold and warm temperatures

    D.-L. Huo / M.-H. Bao / J. Cao / Z.-J. Zhao

    The European Zoological Journal, Vol 89, Iss 1, Pp 190-

    2022  Volume 203

    Abstract: The adaptive adjustments in the capacity for metabolic thermogenesis are critical for the survival in many small mammals that are acclimated to cold winter conditions. In this study the striped hamsters (Cricetulus barabensis) were subjected to repeated ... ...

    Abstract The adaptive adjustments in the capacity for metabolic thermogenesis are critical for the survival in many small mammals that are acclimated to cold winter conditions. In this study the striped hamsters (Cricetulus barabensis) were subjected to repeated cycles of cold (5°C) and warm (23°C) temperatures. Resting metabolic rate (RMR), nonshivering thermogenesis (NST) and energy intake, as well as the expression of uncoupling protein 1 (UCP1) of brown adipose tissue (BAT) and serum thyroid hormone levels were measured. Both RMR and NST were significantly increased in striped hamsters subjected to repeated cycles of short-term cold (5°C, 72 h) – warm (23°C, 4 days) temperatures compared to that of the hamsters consistently kept at 23°C. In these cycled hamsters, BAT UCP1 expression was significantly upregulated, whereas serum T3 and T4 concentration did not change significantly. Moreover, gross energy intake was considerably increased during both cold exposure and warm phases, whereas fat deposition was significantly decreased in these cycled hamsters compared to those consistently kept at 23°C. This indicates that small mammals may both increase energy intake and mobilize fat depots to cope with frequent cold exposure. Thyroid hormone may be not involved in the BAT UCP1-mediated thermogenesis and fat mobilization.
    Keywords energy intake ; fat deposit ; striped hamsters ; thermogenesis ; thyroid hormone ; uncoupling protein 1 (ucp1) ; Zoology ; QL1-991
    Language English
    Publishing date 2022-12-01T00:00:00Z
    Publisher Taylor & Francis Group
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  6. Article ; Online: AsiaRiceYield4km

    H. Wu / J. Zhang / Z. Zhang / J. Han / J. Cao / L. Zhang / Y. Luo / Q. Mei / J. Xu / F. Tao

    Earth System Science Data, Vol 15, Pp 791-

    seasonal rice yield in Asia from 1995 to 2015

    2023  Volume 808

    Abstract: Rice is the most important staple food in Asia. However, high-spatiotemporal-resolution rice yield datasets are limited over this large region. The lack of such products greatly hinders studies that are aimed at accurately assessing the impacts of ... ...

    Abstract Rice is the most important staple food in Asia. However, high-spatiotemporal-resolution rice yield datasets are limited over this large region. The lack of such products greatly hinders studies that are aimed at accurately assessing the impacts of climate change and simulating agricultural production. Based on annual rice maps in Asia, we incorporated multisource predictors into three machine learning (ML) models to generate a high-spatial-resolution (4 km) seasonal rice yield dataset (AsiaRiceYield4km) for the 1995–2015 period. Predictors were divided into four categories that considered the most comprehensive rice growth conditions, and the optimal ML model was determined based on an inverse probability weighting method. The results showed that AsiaRiceYield4km achieves good accuracy for seasonal rice yield estimation (single rice: R 2 =0.88 , RMSE = 920 kg ha −1

    double rice: R 2 =0.91 , RMSE = 554 kg ha −1

    and triple rice: R 2 =0.93 , RMSE = 588 kg ha −1 ). Compared with single rice from the Spatial Production Allocation Model (SPAM), the R 2 of AsiaRiceYield4km was improved by 0.20, and the RMSE was reduced by 618 kg ha −1 on average. In particular, constant environmental conditions, including longitude, latitude, elevation and soil properties, contributed the most ( ∼ 45 %) to rice yield estimation. For different rice growth periods, we found that the predictors of the reproductive period had greater impacts on rice yield prediction than those of the vegetative period and the whole growing period. AsiaRiceYield4km is a novel long-term gridded rice yield dataset that can fill the unavailability of high-spatial-resolution seasonal yield products across major rice production areas and promote more relevant studies on agricultural sustainability worldwide. AsiaRiceYield4km can be downloaded from the following open-access data repository: https://doi.org/10.5281/zenodo.6901968 (Wu et al., 2022).
    Keywords Environmental sciences ; GE1-350 ; Geology ; QE1-996.5
    Subject code 333
    Language English
    Publishing date 2023-02-01T00:00:00Z
    Publisher Copernicus Publications
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  7. Article ; Online: Sinking fate and carbon export of zooplankton fecal pellets

    H. Wang / Z. Liu / J. Li / B. Lin / Y. Zhao / X. Zhang / J. Cao / J. Zhang / H. Song / W. Wang

    Biogeosciences, Vol 20, Pp 5109-

    insights from time-series sediment trap observations in the northern South China Sea

    2023  Volume 5123

    Abstract: The sinking of zooplankton fecal pellets is a key process in the marine biological carbon pump, facilitating the export of particulate organic carbon (POC). Here, we analyzed zooplankton fecal pellets collected by two time-series sediment traps deployed ... ...

    Abstract The sinking of zooplankton fecal pellets is a key process in the marine biological carbon pump, facilitating the export of particulate organic carbon (POC). Here, we analyzed zooplankton fecal pellets collected by two time-series sediment traps deployed on mooring TJ-A1B in the northern South China Sea (SCS) from May 2021 to May 2022. The results show a seasonal variability in both fecal pellet numerical (FPN) flux and fecal pellet carbon (FPC) flux, with peaks in November to April and June to August. It implies that the fecal pellet flux is largely regulated by the East Asian monsoon system. Vertical analysis further shows that FPN and FPC fluxes are higher at 1970 than at 500 m water depth, with larger pellets occurring in the deeper water, indicating a significant influence of mesopelagic and bathypelagic zooplankton community and lateral transport on deep-sea FPC export. However, the biovolume of amorphous pellets decreases significantly from 500 to 1970 m water depth, implying that these fecal pellets are broken and fragmented during the sinking process, possibly due to zooplankton grazing and disturbance by deep-sea currents. The contribution of fecal pellets to total POC export in the northern SCS is on average 3.4 % and 1.9 % at 500 and 1970 m water depth, respectively. This study highlights that the sinking fate of fecal pellets is regulated by marine primary productivity, deep-sea-dwelling zooplankton communities, and deep-sea currents in the tropical marginal sea, thus providing a new perspective for exploring the carbon cycle in the world ocean.
    Keywords Ecology ; QH540-549.5 ; Life ; QH501-531 ; Geology ; QE1-996.5
    Subject code 551
    Language English
    Publishing date 2023-12-01T00:00:00Z
    Publisher Copernicus Publications
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  8. Article ; Online: Measurement report

    H. Liu / Q. Wang / L. Xing / Y. Zhang / T. Zhang / W. Ran / J. Cao

    Atmospheric Chemistry and Physics, Vol 21, Pp 973-

    quantifying source contribution of fossil fuels and biomass-burning black carbon aerosol in the southeastern margin of the Tibetan Plateau

    2021  Volume 987

    Abstract: Anthropogenic emissions of black carbon (BC) aerosol are transported from Southeast Asia to the southwestern Tibetan Plateau (TP) during the pre-monsoon; however, the quantities of BC from different anthropogenic sources and the transport mechanisms are ... ...

    Abstract Anthropogenic emissions of black carbon (BC) aerosol are transported from Southeast Asia to the southwestern Tibetan Plateau (TP) during the pre-monsoon; however, the quantities of BC from different anthropogenic sources and the transport mechanisms are still not well constrained because there have been no high-time-resolution BC source apportionments. Intensive measurements were taken in a transport channel for pollutants from Southeast Asia to the southeastern margin of the TP during the pre-monsoon to investigate the influences of fossil fuels and biomass burning on BC. A receptor model that coupled multi-wavelength absorption with aerosol species concentrations was used to retrieve site-specific Ångström exponents (AAEs) and mass absorption cross sections (MACs) for BC. An “aethalometer model” that used those values showed that biomass burning had a larger contribution to BC mass than fossil fuels (BC biomass =57 % versus BC fossil =43 %). The potential source contribution function indicated that BC biomass was transported to the site from northeastern India and northern Burma. The Weather Research and Forecasting model coupled with chemistry (WRF-Chem) indicated that 40 % of BC biomass originated from Southeast Asia, while the high BC fossil was transported from the southwest of the sampling site. A radiative transfer model indicated that the average atmospheric direct radiative effect (DRE) of BC was + 4.6 ± 2.4 W m −2 , with + 2.5 ± 1.8 W m −2 from BC biomass and + 2.1 ± 0.9 W m −2 from BC fossil . The DRE of BC biomass and BC fossil produced heating rates of 0.07 ± 0.05 and 0.06 ± 0.02 K d −1 , respectively. This study provides insights into sources of BC over a transport channel to the southeastern TP and the influence of the cross-border transportation of biomass-burning emissions from Southeast Asia during the pre-monsoon.
    Keywords Physics ; QC1-999 ; Chemistry ; QD1-999
    Subject code 511
    Language English
    Publishing date 2021-01-01T00:00:00Z
    Publisher Copernicus Publications
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  9. Article ; Online: The RapeseedMap10 database

    J. Han / Z. Zhang / Y. Luo / J. Cao / L. Zhang / J. Zhang / Z. Li

    Earth System Science Data, Vol 13, Pp 2857-

    annual maps of rapeseed at a spatial resolution of 10 m based on multi-source data

    2021  Volume 2874

    Abstract: Large-scale, high-resolution maps of rapeseed ( Brassica napus L.), a major oilseed crop, are critical for predicting annual production and ensuring global energy security, but such maps are still not freely available for many areas. In this study, we ... ...

    Abstract Large-scale, high-resolution maps of rapeseed ( Brassica napus L.), a major oilseed crop, are critical for predicting annual production and ensuring global energy security, but such maps are still not freely available for many areas. In this study, we developed a new pixel- and phenology-based algorithm and produced a new data product for rapeseed planting areas (2017–2019) in 33 countries at 10 m spatial resolution based on multiple data. Our product is strongly consistent at the national level with official statistics of the Food and Agricultural Organization of the United Nations. Our rapeseed maps achieved F1 spatial consistency scores of at least 0.81 when compared with the Cropland Data Layer in the United States, the Annual Crop Inventory in Canada, the Crop Map of England, and the Land Cover Map of France. Moreover, F1 scores based on independent validation samples ranged from 0.84 to 0.91, implying a good consistency with ground truth. In almost all countries covered in this study, the rapeseed crop rotation interval was at least 2 years. Our derived maps suggest, with reasonable accuracy, the robustness of the algorithm in identifying rapeseed over large regions with various climates and landscapes. Scientists and local growers can use the freely downloadable derived rapeseed planting areas to help predict rapeseed production and optimize planting structures. The product is publicly available at https://doi.org/10.17632/ydf3m7pd4j.3 (Han et al., 2021).
    Keywords Environmental sciences ; GE1-350 ; Geology ; QE1-996.5
    Subject code 333
    Language English
    Publishing date 2021-06-01T00:00:00Z
    Publisher Copernicus Publications
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  10. Article ; Online: Genetic, haplotype and phylogenetic analysis of Ligula intestinalis by using mt-CO1 gene marker

    M. A. Selcuk / F. Celik / S. Simsek / H. Ahmed / H. K. Kesik / S. Gunyakti Kilinc / J. Cao

    Brazilian Journal of Biology, Vol

    ecological implications, climate change and eco-genetic diversity

    2022  Volume 84

    Abstract: Abstract Ligula intestinalis is a cestode parasite that affects freshwater fish in different countries of the world. The current study aims to reveal the phylogenetic, genetic and haplotype diversity of mt-CO1 gene sequences sent to the NCBI database ... ...

    Abstract Abstract Ligula intestinalis is a cestode parasite that affects freshwater fish in different countries of the world. The current study aims to reveal the phylogenetic, genetic and haplotype diversity of mt-CO1 gene sequences sent to the NCBI database from different countries by using in-silico analysis. The 105 mt-CO1 (371 bp) gene sequences of L. intestinalis obtained from NCBI were used for bioinformatics analyses. Sequences were subjected to phylogenetic and haplotype analysis. As a result of the haplotype analysis of L. intestinalis, 38 haplotypes were obtained from 13 different countries. Hap24 constituted 44.76% of the obtained haplotype network. Changes in nucleotides between haplotypes occurred at 1-84 different points. China and Turkey have highest fixation index (Fst) values of 0.59761, while the lowest (-0.10526) was found between Russia and Turkey. This study provides a baseline for future studies on extensive scale on the epidemiology, ecological aspects, distribution pattern, transmission dynamics and population dispersion of L. intestinalis worldwide.
    Keywords Ligula intestinalis ; genetic variation ; mt-CO1 ; in-silico analysis ; Science ; Q ; Biology (General) ; QH301-705.5 ; Zoology ; QL1-991 ; Botany ; QK1-989
    Subject code 572
    Language English
    Publishing date 2022-06-01T00:00:00Z
    Publisher Instituto Internacional de Ecologia
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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