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1.
Artículo en Inglés | MEDLINE | ID: mdl-33809493

RESUMEN

The dispersion of small aerosols in a concert hall is experimentally studied for estimating the risk of infection with SARS-CoV-2 during a concert. A mannequin was modified to emit an air stream containing aerosols and CO2. The aerosols have a size distribution with a peak diameter (δ) close to 0.3 µm and a horizontal initial particle velocity (vp,x) of 2.4 m/s. The CO2-concentration (c) emitted simultaneously is 7500 ppm. It is investigated, if the spatial dissipation of aerosols and CO2 can be correlated. This would allow the use of technically easier CO2 measurements to monitor compliance with aerosol concentration limits. Both aerosol and CO2 concentrations are mapped by different sensors placed around the mannequin. As a result, no significant enrichment of aerosols and CO2 was obtained outside a radius of 1.5 m when the fresh air ventilation in the concert hall has a steady vertical flow with a velocity of vg,z=0.05 m/s and the installed ventilation system was operating at an air change rate per hour (ACH) of 3, corresponding to an air exchange rate of 51,000 m3/h. A Pearson correlation coefficient of 0.77 was obtained for CO2 and aerosol concentrations measured simultaneously at different positions within the concert hall.


Asunto(s)
Aerosoles , Dióxido de Carbono , Humanos , Ventilación
2.
Huan Jing Ke Xue ; 42(2): 988-995, 2021 Feb 08.
Artículo en Chino | MEDLINE | ID: mdl-33742895

RESUMEN

The rhizosphere priming effect (RPE) caused by carbon inputs from crop rhizodeposits plays a key role in regulating the carbon emission flux and carbon balance of farmland soils. Due to frequent alternations between dry and wet conditions, CO2 and CH4 emissions and the RPE in paddy field ecosystems are significantly different to those of other ecosystems. Therefore, it is of great significance to determine the direction and intensity of the rice RPE under alternations of dry and wet to limit greenhouse gas emissions. In this study, using a 13C-CO2 continuous labeling method combined with a pot-based experiment, the response of rice growth and the RPE under alternating dry and wet and continuous flooding conditions was examined. The results showed that, compared with the continuous flooding treatment, the alternating dry and wet treatments significantly increased aboveground and root biomass and the root-to-root ratio, and also increased soil microbial biomass. Under continuous flooding conditions, fluxes of 13CO2 and 13CH4 increased with rice growth from 10.2 µg·(kg·h)-1 and 2.8 µg·(kg·h)-1 (63 d) to 16.0 µg·(kg·h)-1 and 3.2 µg·(kg·h)-1 (75 d), respectively. During the 12-day drying process, the emissions of 13CO2 and 13CH4 derived from rhizosphere deposited C decreased by 57.5% and 88.1%. Under continuous flooding conditions, the RPE for CO2 and CH4 were positive and increased with the growth of rice. Under the alternating dry and wet treatment, after 12 days of drying, the RPE for CO2 and CH4 was reduced from 0.29 mg·(kg·h)-1 and 12.3 µg·(kg·h)-1 (63 d) to -0.39 mg·(kg·h)-1 and 0.07 µg·(kg·h)-1 (75 d). Thus, alternating wet and dry treatment can effectively promote rice growth and reduce the cumulative emissions of CH4. Therefore, adopting appropriate field water management is of great significance for increasing rice yields and mitigating greenhouse gas emissions.


Asunto(s)
Oryza , Suelo , Agricultura , Dióxido de Carbono/análisis , Ecosistema , Metano , Óxido Nitroso/análisis , Rizosfera , Agua , Abastecimiento de Agua
3.
Sci Total Environ ; 764: 142875, 2021 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-33757245

RESUMEN

Lichens contribute significantly to the biodiversity and functioning of many ecosystems. Although lichens are useful air pollution bioindicators and may respond in significant ways to global change, they are studied infrequently under field conditions in chamberless exposure systems. We surveyed corticolous lichens on paper birch (Betula papyrifera) and trembling aspen (Populus tremuloides) after 10 years exposure (1998-2007) to elevated CO2 (eCO2) and O3 (eO3) in the Aspen-FACE experiment in Rhinelander, WI, USA. This experiment utilized chamberless exposure rings, 30 m in diameter, with both host trees planted together in one quadrant. Four treatments were allocated among 12 rings: ambient, eCO2, eO3, and the combination of eCO2 + eO3, each replicated once in each of three blocks. Over the course of the experiment, ambient CO2 increased from 343 to 386 ppm while eCO2 averaged ~530 ppm CO2. Ambient ozone concentrations averaged ~37 ppb and ~49 ppb for eO3 although exposures decreased with time. Tree growth and leaf area index were negatively affected by eO3 and stimulated by eCO2, resulting in higher photosynthetically active radiation (PAR) in eO3 and lower in eCO2. We assessed lichen richness and cover on five host trees per ring on the north-facing side of the trunks, which were higher on birch than on aspen. Neither of the lichen measures on birch responded to the exposure treatments, while on aspen lichen cover was highest in eO3 and lowest in eCO2. On aspen, lichen cover was positively related to PAR and dominated by Caloplaca. No relationship was found for birch, although Lecanora exhibited a negative relationship with PAR. These lichens were insensitive to direct effects of eCO2 and eO3 at the levels applied. Instead, they responded to indirect effects, such as host tree species, and changes in understory PAR, resulting from direct effects of eO3 and eCO2 on the host trees.


Asunto(s)
Líquenes , Ozono , Dióxido de Carbono/toxicidad , Ecosistema , Ozono/toxicidad , Árboles
4.
AAPS PharmSciTech ; 22(3): 106, 2021 Mar 14.
Artículo en Inglés | MEDLINE | ID: mdl-33719021

RESUMEN

Masking the unpleasant taste of the pharmaceutically active ingredients plays a critical role in patient acceptance, particularly for children. This work's primary objective was the preparation of taste-masked ibuprofen microparticles using cocoa butter with the assistance of supercritical fluid technology. Microparticles were prepared by dissolving ibuprofen in melted cocoa butter at 40 °C. The solution was then introduced into a supercritical fluid unit and processed at 10 MPa CO2 pressure for 30 min. The product was collected after depressurizing the system. The effect of the drug to cocoa butter ratio and the supercritical fluid units' configuration on product quality was evaluated and compared with the sample prepared by a conventional method. Physicochemical characterization of the prepared product, including particle size, crystallinity, entrapment efficiency, in vitro drug release, and product taste using a human volunteer panel was conducted. The produced microparticles were in the range of 1.42 to 15.28 µm. The entrapment efficiency of the formulated microparticles ranged from 66 to 81%. The drug:polymer ratio, the configuration of the supercritical fluid unit, and the method of preparation were found to have a critical role in the formulation of ibuprofen microparticles. Taste evaluation using human volunteers showed that microparticles containing 20% drug and processed with supercritical fluid technology were capable of masking the bitter taste of ibuprofen. In conclusion, the dispersion of ibuprofen in cocoa butter using supercritical fluid technology is a a promising innovative method to mask the bitter taste of ibuprofen.


Asunto(s)
Dióxido de Carbono/química , Cromatografía con Fluido Supercrítico/métodos , Grasas de la Dieta/síntesis química , Desarrollo de Medicamentos/métodos , Ibuprofeno/síntesis química , Gusto/efectos de los fármacos , Antiinflamatorios no Esteroideos/administración & dosificación , Antiinflamatorios no Esteroideos/síntesis química , Antiinflamatorios no Esteroideos/farmacocinética , Grasas de la Dieta/administración & dosificación , Grasas de la Dieta/farmacocinética , Humanos , Ibuprofeno/administración & dosificación , Ibuprofeno/farmacocinética , Tamaño de la Partícula , Gusto/fisiología , Difracción de Rayos X/métodos
5.
J Environ Sci (China) ; 103: 268-278, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33743908

RESUMEN

In this work, the waste biomass lotus leaf was converted into N-doped porous carbonaceous CO2 adsorbents. The synthesis process includes carbonization of lotus leaf, melamine post-treatment and KOH activation. For the resultant sorbents, high nitrogen content can be contained due to the melamine modification and advanced porous structure were formed by KOH etching. These samples were carefully characterized by different techniques and their CO2 adsorption properties were investigated in detail. These sorbents hold good CO2 adsorption abilities, up to 3.87 and 5.89 mmol/g at 25 and 0°C under 1 bar, respectively. By thorough investigation, the combined interplay of N content and narrow microporous volume was found to be responsible for the CO2 uptake for this series of sorbents. Together with the high CO2 adsorption abilities, these carbons also display excellent reversibility, high CO2/N2 selectivity, applicable heat of adsorption, fast CO2 adsorption kinetics and good dynamic CO2 adsorption capacity. This study reveals a universal method of obtaining N-doped porous carbonaceous sorbents from leaves. The low cost of raw materials accompanied by easy synthesis procedure disclose the enormous potential of leaves-based carbons in CO2 capture as well as many other applications.


Asunto(s)
Lotus , Nitrógeno , Dióxido de Carbono , Hojas de la Planta , Porosidad
6.
J Environ Sci (China) ; 103: 279-287, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33743909

RESUMEN

Capturing flue gases often require multiple stages of scrubbing, increasing the capital and operating costs. So far, no attempt has been made to study the absorption characteristics of all the three gases (NO, SO2 and CO2) in a single stage absorption unit at alkaline pH conditions. We have attempted to capture all the three gases with a single wet scrubbing column. The absorption of all three gases with sodium carbonate solution promoted with oxidizers was investigated in a tall absorption column. The absorbance was found to be 100% for CO2, 30% for NO and 95% for SO2 respectively. The capture efficiency of sodium carbonate solution was increased by 40% for CO2 loading, with the addition of oxidizer. Absorption kinetics and reaction pathways of all the three gases were discussed individually in detail.


Asunto(s)
Dióxido de Carbono , Dióxido de Azufre , Cinética
7.
J Environ Manage ; 286: 112232, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33676132

RESUMEN

Achieving reliable energy supply and environment sustainability whereby mitigating CO2 emissions and promoting sustainable development has become a global effort. Thus, the current study intends to verify the non-linear influence effects of natural gas, nuclear energy, renewable energy and information and communication technology trade on economic growth and carbon dioxide emission in ten leading CO2 emitter countries from 20002016. The panel regression, such as pooled regression, model fixed effect, random effects, robust least squares and panel causation procedures are applied for panel data appraisal. The regression analysis results mention that nuclear energy, renewable energy, and Information and communication technology (ICT-trade) stimulate economic growth, whereas environmental results illustrate that renewable energy and ICT-trade contribute to eliminating CO2 emissions. The causality findings indicate that renewable energy consumption and ICT trade cause economic growth as well as CO2 emissions. Therefore, policymakers should invigorate to exploit renewable energy and achieve the benefits from the significant influence of economic growth and a clean environment through the potential of green ICT-trade.


Asunto(s)
Dióxido de Carbono , Gas Natural , Dióxido de Carbono/análisis , Desarrollo Económico , Políticas , Energía Renovable
8.
Bioresour Technol ; 329: 124915, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33684840

RESUMEN

CO2 production during ensiling is a source of greenhouse gases emissions and a cause of nutrient loss of silage. To investigate the influence of additives on CO2 production and relevant bacterial communities, stylo and rice straw were ensiled with sucrose and Lactobacillus plantarum (LP). After 30 days fermentation, LP reduced CO2 production (from 66.2 to 0 mL/100 g fresh matter in stylo, from 83.7 to 16.6 mL/100 g fresh matter in rice straw) and weight loss (from 2.71 to 1.72% in stylo, from 2.75 to 2.40% in rice straw). CO2 production was positively correlated (P < 0.05) with Lactococcus (0.99), Leuconostoc (0.55), Lachnoclostridium (0.45), Prevotella (0.23) and was negatively correlated (P < 0.05) with Serratia (-0.66), Sphingobacterium (-0.58), Pediococcus (-0.36). LP decreased the relative abundance of genera positively correlated with CO2 production and increased that of genera negatively correlated. In conclusion, LP could reduce CO2 production by altering bacterial community during ensiling.


Asunto(s)
Inoculantes Agrícolas , Dióxido de Carbono , Fermentación , Ácido Láctico , Nutrientes , Ensilaje/análisis
9.
J Environ Manage ; 286: 112210, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33721604

RESUMEN

CO2 reduction has become one of the most critical issues globally, and considering sustainable development, many countries are implementing and reviewing CO2 reduction policies. To examine the effect of the CO2 reduction policies, a forecasting model that considers the relationship between variables such as population, building area, industries, vehicle use, and the environment is required. Moreover, this model should also be applicable to various cities to support effective policymaking. In this study, we develop a model that can predict CO2 emissions from the relationship between the variables using System Dynamics, a method to model cities to represent one system composed of various variables. To expand the applicability of the model to various cities in Japan, the proposed model assigns statistical data as input data that can be obtained in any city and standardizes the system structure and variables of the model. In this study, we selected three cities, namely Fukuoka, Kashiwa, and Kumano, which had different populations and industrial characteristics. The calculation accuracy error of CO2 emissions for the three cities was found to be less than 6%. In addition, through the parameter study, it was confirmed that the proposed model can be used to examine the sectors that require CO2 reduction policies, along with the optimal application period. This study aims to provide an effective model that can help in CO2 forecasting and thus in environmental and sustainable development policymaking. Our approach to the CO2 forecasting model facilitates calculating effective CO2 reductions in various cities.


Asunto(s)
Dióxido de Carbono , Industrias , Dióxido de Carbono/análisis , Ciudades , Predicción , Japón
10.
Bioresour Technol ; 330: 124952, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33744739

RESUMEN

This research investigates the treatment efficiency and greenhouse gas (GHG) emissions of non-floating and floating bed AS systems with acclimatized sludge treating landfill leachate. The GHGs under study included carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). The non-floating and floating bed AS systems were operated in parallel with identical landfill leachate influent under different hydraulic retention time (HRT) conditions (24, 18, and 12 h). The experimental results showed that the treatment efficiency of organic compounds under 24 h HRT of both systems (90 - 98%) were insignificantly different, while the nutrient removal efficiency of both systems were between 54 and 98 %. The treatment efficiency of the floating bed AS system, despite shorter HRT, remained relatively unchanged due to an abundance of effective bacteria residing in the floating media. The CO2 emissions were insignificantly different between both AS systems under all HRT conditions (22 - 26.3 µmol/cm2.min). The CO2 emissions were positively correlated with organic loading but inversely correlated with HRT. The CH4 emissions were positively correlated with HRT (26.3 µmol/cm2.min under 24 h HRT of the floating bed AS system). The N2O emissions were positively correlated with nitrogen loading, and the N2O emissions from the floating bed AS system were lower due to an abundance of N2O-reducing bacteria. The floating media enhanced the biological treatment efficiency while maintaining the bacterial community in the system. However, the floating media promoted CH4 production under anoxic conditions. The originality of this research lies in the use of floating media in the biological treatment system to mitigate GHG emissions, unlike existing research which focused primarily on enhancement of the treatment efficiency.


Asunto(s)
Gases de Efecto Invernadero , Contaminantes Químicos del Agua , Dióxido de Carbono/análisis , Efecto Invernadero , Metano/análisis , Óxido Nitroso/análisis , Aguas del Alcantarillado , Contaminantes Químicos del Agua/análisis
12.
Sci Adv ; 7(10)2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33674320

RESUMEN

The COVID-19 (coronavirus disease 2019) pandemic has resulted in a marked slowdown in greenhouse gas and aerosol emissions. Although the resulting emission reductions will continue to evolve, this will presumably be temporary. Here, we provide estimates of the potential effect of such short-term emission reductions on global and regional temperature and precipitation by analyzing the response of an Earth System Model to a range of idealized near-term emission pathways not considered in available model intercomparison projects. These estimates reveal the modest impact that temporary emission reductions associated with the COVID-19 pandemic will have on global and regional climate. Our simulations suggest that the impact of carbon dioxide and aerosol emission reductions is actually a temporary enhancement in warming rate. However, our results demonstrate that even large emission reductions applied for a short duration have only a small and likely undetectable impact.


Asunto(s)
Clima , Efecto Invernadero/prevención & control , Aire , Dióxido de Carbono/análisis , Internacionalidad , Lluvia , Temperatura , Factores de Tiempo
13.
Water Sci Technol ; 83(5): 1108-1117, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33724940

RESUMEN

It is difficult to adjust the pH of oil acidized wastewater rich in Ca2+, thus hindering the polyacrylamide (PAM) flocculation. This study aims at accelerating the flocculation process by introducing CO2 into the water to induce the formation of CaCO3 nuclei. The order in which CO2 and NaOH were added affected the floc structures. Compared with CO2-NaOH-PAM, the flocs of NaOH-CO2-PAM were more compact and more CaCO3 crystals were formed. The aqueous Ca2+ involved in the reaction reached 20%, and CO2 utilization was enhanced. The settling time was shortened by half (from 20 to 3 min), and NaOH consumption was reduced by one-tenth (from 0.03 to 0.003 mol), hence significantly reducing the costs. Due to the higher settling rate and shorter contact time, the NaOH-CO2-PAM flocs adsorbed less so that the residual oil was 124 mg·L-1, while in the case of CO2-NaOH-PAM it was 88 mg·L-1. As a promising coagulation aid, CO2 can also be used to mineralize pollutants in wastewater.


Asunto(s)
Contaminantes Ambientales , Purificación del Agua , Dióxido de Carbono , Costos y Análisis de Costo , Floculación , Aguas Residuales
14.
Medicine (Baltimore) ; 100(8): e24892, 2021 Feb 26.
Artículo en Inglés | MEDLINE | ID: mdl-33663119

RESUMEN

RATIONALE: Carbon dioxide pneumoperitoneum in laparoscopic surgery can bring about occult perioperative cerebral infarction, advancing our understanding of the causes of severe postoperative delayed recovery. PATIENT CONCERNS: Here, we report the case of a 35-year-old woman who underwent a right renal tumor resection in our institution, during which a raised pneumoperitoneum pressure (from 15 to 20 mm Hg) was adopted by the surgeon to prevent errhysis and to help stop the bleeding. Despite an accidental minor tearing of the inferior vena cava, vital signs remained stable throughout the procedure, and no obvious abnormality was observed in either end tidal carbon dioxide values or blood gas analysis. However, the patient unexpectedly suffered delayed recovery after the operation, presenting incomplete left hemiplegia and a positive Babinski sign. DIAGNOSES: Perioperative stroke was diagnosed by anesthesiologists, after excluding the effects of anesthesia. Cerebral hemorrhage was excluded, as no obvious abnormality was found in the density of brain parenchyma in the emergency computed tomography examination, and a digital subtraction angiography showed no abnormal thrombosis. Further magnetic resonance diagnosis led us to consider diffuse gas embolisms to be the cause of this acute stroke; a right echocardiography revealed that a patent foramen ovale (PFO) may account for the global cerebral gas embolisms. INTERVENTIONS: The patient received neuroprotective drugs (Vinpocetine, Edaravone, and Xingnaojing, which are commonly used as a standard of care in China), antiplatelets and other symptomatic treatments, plus dexamethasone to relieve edema. A contrast-enhanced echocardiography of the right heart was performed, the results of which were consistent with the sonography of a PFO. OUTCOMES: The patient was hospitalized for 14 days and eventually discharged after recovery. At the latest follow-up in August 2019, the patient recovered without residual neurological sequelae. LESSONS: Our results emphasize the need for vigilance regarding adverse cardiovascular and neurological events caused by carbon dioxide gas embolisms when encountering the inadvertent situation of vessels rupturing. Timely monitoring of paradoxical gas embolism by transoesophageal echocardiography is necessary and can avert the risk of severe complications. Urgent consideration should be given to stopping pneumoperitoneum and switching to laparotomy for hemostasis so that the patient can obtain the best benefit-risk ratio.


Asunto(s)
Dióxido de Carbono/análisis , Infarto Cerebral/etiología , Embolia Paradójica/complicaciones , Nefrectomía/efectos adversos , Vena Cava Inferior/lesiones , Adulto , Infarto Cerebral/diagnóstico por imagen , Ecocardiografía Transesofágica , Femenino , Humanos , Insuflación/efectos adversos , Complicaciones Intraoperatorias , Imagen por Resonancia Magnética , Periodo Perioperatorio , Vena Cava Inferior/diagnóstico por imagen
15.
Sci Total Environ ; 768: 144477, 2021 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-33736314

RESUMEN

Copper ferrite/reduced graphene oxide (CF/rGO) nanocomposites (NCs) was synthesized using the bio-combustion method and applied as a cathode catalyst in the microbial reduction of CO2 to volatile fatty acids (VFAs) in a single chamber microbial electrosynthesis system (MES). The synthesized NCs exhibited a porous network-like structure with a high surface area of CF/rGO (158.22 m2/g), which was 2.24 folds higher than that of CF. The Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS) analysis for CF/rGO/Carbon cloth (Cc) revealed a high reduction current density of -7.3 A/m2 and a low charge transfer resistance of 2.8 Ω. The isobutyrate and acetate in MES-2 (Cu/rGO/Cc) were produced at 35.37 g/m2/d, which was 1.53 folds higher than that of MES-1 (bare Cc: 23.10 g/m2/d). The columbic efficiency (77.78%) and total VFA concentration (1941.13 ± 83 mg COD/L) were noted to be 1.97 and 1.6 folds higher for MES-2 than MES-1, respectively. The Tafel plot drawn from the CV curves exhibited an exchange current density value of MES-2 that was 3.46 A/m2, and this value was 1.19 and 33.92 folds higher than that of MES-1 and abiotic CF/rGO/Cc, respectively. Field emission scanning electron microscopy (FESEM) observations revealed enhanced rod-shaped bacteria had grown on the cathode suggesting excellent biocompatible and multi-length scale porosity of CF/rGO catalysts for enhanced colonization of microbes. The phyla Proteobacteria (Betaproteobacteria), Bacteroidetes, and Firmicutes were highly abundant as the dominant microbial communities on the cathode, which might played a major role in bioelectrochemical CO2 reduction to VFAs. The results from this study clearly demonstrate that the CF/rGO/Cc electrode could serve as a conductive element between microbes and bactericidal electrodes with excellent electrochemical properties to enable performance of the MES.


Asunto(s)
Dióxido de Carbono , Cobre , Electrodos , Ácidos Grasos Volátiles , Compuestos Férricos , Grafito
16.
Sci Total Environ ; 768: 144899, 2021 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-33736351

RESUMEN

Tropical plant species are vulnerable to climate change and global warming. Since flowering is a critical factor for plant reproduction and seed-set, warming and elevated atmospheric carbon dioxide concentrations (eCO2) are crucial climate change factors that can affect plant reproductive dynamics and flowering related events in the tropics. Using a combined free-air CO2 enrichment and a free-air temperature-controlled enhancement system, we investigate how warming (+2 °C above ambient, eT) and elevated [CO2] (~600 ppm, eCO2) affect the phenological pattern, plant-insect interactions, and outcrossing rates in the tropical legume forage species Stylosanthes capitata Vogel (Fabaceae). In comparison to the control, a significantly greater number of flowers (NF) per plot (+62%) were observed in eT. Furthermore, in warmed plots flowers began opening approximately 1 h earlier (~09:05), with a canopy temperature of ~23 °C, than the control (~09:59) and eCO2 (~09:55) treatments. Flower closure occurred about 3 h later in eT (~11:57) and control (~13:13), with a canopy temperature of ~27 °C. These changes in flower phenology increased the availability of floral resources and attractiveness for pollinators such as Apis mellifera L. and visitors such as Paratrigona lineata L., with significant interactions between eT treatments and insect visitation per hour/day, especially between 09:00-10:40. In comparison to the control, the additive effects of combined eCO2 + eT enhanced the NF by 137%, while the number of A. mellifera floral visits per plot/week increased by 83% during the period of greatest flower production. Although we found no significant effect of treatments on mating system parameters, the overall mean multilocus outcrossing rate (tm = 0.53 ± 0.03) did confirm that S. capitata has a mixed mating system. The effects of elevated [CO2] and warming on plant-pollinator relationships observed here may have important implications for seed production of tropical forage species in future climate scenarios.


Asunto(s)
Dióxido de Carbono , Reproducción , Animales , Abejas , Cambio Climático , Flores , Insectos , Polinización
17.
JAMA Netw Open ; 4(3): e210414, 2021 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-33651109

RESUMEN

Importance: Face masks have been associated with effective prevention of diffusion of viruses via droplets. However, the use of face masks among children, especially those aged younger than 3 years, is debated, and the US Centers for Disease Control and American Academy of Physicians recommend the use of face mask only among individuals aged 3 years or older. Objective: To examine whether the use of surgical facial masks among children is associated with episodes of oxygen desaturation or respiratory distress. Design, Setting, and Participants: This cohort study was conducted from May through June 2020 in a secondary-level hospital pediatric unit in Italy. Included participants were 47 healthy children divided by age (ie, group A, aged ≤24 months, and group B, aged >24 months to ≤144 months). Data were analyzed from May through June 2020. Interventions: All participants were monitored every 15 minutes for changes in respiratory parameters for the first 30 minutes while not wearing a surgical face mask and for the next 30 minutes while wearing a face mask. Children aged 24 months and older then participated in a walking test for 12 minutes. Main Outcomes and Measures: Changes in respiratory parameters during the use of surgical masks were evaluated. Results: Among 47 children, 22 children (46.8%) were aged 24 months or younger (ie, group A), with 11 boys (50.0%) and median (interquartile range [IQR]) age 12.5 (10.0-17.5) months, and 25 children (53.2%) were aged older than 24 months to 144 months or younger, with 13 boys (52.0%) and median (IQR) age 100.0 (72.0-120.0) months. During the first 60 minutes of evaluation in the 2 groups, there was no significant change in group A in median (IQR) partial pressure of end-tidal carbon dioxide (Petco2; 33.0 [32.0-34.0] mm Hg; P for Kruskal Wallis = .59), oxygen saturation (Sao2; 98.0% [97.0%-99.0%]; P for Kruskal Wallis = .61), pulse rate (PR; 130.0 [115.0-140.0] pulsations/min; P for Kruskal Wallis = .99), or respiratory rate (RR; 30.0 [28.0-33.0] breaths/min; P for Kruskal Wallis = .69) or for group B in median (IQR) Petco2 (36.0 [34.0-38.0] mm Hg; P for Kruskal Wallis = .97), Sao2 (98.0% [97.0%-98.0%]; P for Kruskal Wallis = .52), PR (96.0 [84.0-104.5] pulsations/min; P for Kruskal Wallis test = .48), or RR (22.0 [20.0-25.0] breaths/min; P for Kruskal Wallis = .55). After the group B walking test, compared with before the walking test, there was a significant increase in median (IQR) PR (96.0 [84.0-104.5] pulsations/min vs 105.0 [100.0-115.0] pulsations/min; P < .02) and RR (22.0 [20.0-25.0] breaths/min vs 26.0 [24.0-29.0] breaths/min; P < .05). Conclusions and Relevance: This cohort study among infants and young children in Italy found that the use of facial masks was not associated with significant changes in Sao2 or Petco2, including among children aged 24 months and younger.


Asunto(s)
/prevención & control , Máscaras/efectos adversos , Pandemias , Respiración , Insuficiencia Respiratoria/etiología , Dióxido de Carbono/fisiología , Preescolar , Femenino , Humanos , Lactante , Italia , Masculino , Oxígeno/sangre , Oxígeno/fisiología , Presión Parcial , Pruebas de Función Respiratoria , Frecuencia Respiratoria
20.
Ying Yong Sheng Tai Xue Bao ; 32(2): 581-590, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33650368

RESUMEN

Studying the effects of rainfall regimes such as rainfall amount and timing on soil carbon mineralization is of great importance for our understanding the mechanisms underlying the stability and accumulation of soil carbon in coastal salt marshes. In this study, we examined the responses of soil carbon mineralization (CO2 and CH4 fluxes) from undisturbed soil columns to rainfall events in different seasons (dry and wet seasons) with filed experiments in a primary Suaeda salsa region in the Yellow River Delta salt-marsh wetland, which is far away from the coast and not affected by tides. The results showed that rainfall amount and timing had a significant interaction in affecting soil CO2 flux rates. During the dry season, large rainfall events significantly reduced soil CO2 flux rates but had no significant effect in the wet season, which might be closely related to the significant increase in soil water content and salinity. Rainfall amount, rainfall timing and their interactions had no significant effect on soil CH4 efflux rates. Rainfall timing and rainfall amount did not affect CH4/CO2. CH4/CO2 increased with increasing soil water content and salinity. Soil water content and soil salinity showed similar increases to increasing rainfall amount. Our results suggested that the changing rainfall regime under climate change in the future would have a great impact on soil carbon mineralization and carbon sink function by regulating soil water and salt migration in this region.


Asunto(s)
Suelo , Humedales , Carbono/análisis , Dióxido de Carbono/análisis , China , Metano/análisis , Ríos
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