RESUMO
PURPOSE: Stereotactic body radiation therapy (SBRT) is a treatment modality with curative intent for oligometastatic cancer patients, commonly defined by a low-burden metastatic disease with 1-5 systemic metastases. Better knowledge of the clinical profile and prognostic factors in oligometastatic cancer patients could help to improve the selection of candidates who may obtain most benefits from SBRT. The objective of this study was to describe the clinical data and outcome in term of overall survival (OS) of patients with oligometastatic disease treated with SBRT over a 6-year period. METHODS: From 2013 to 2018, 284 solid tumor cancer patients with 1-5 oligometastases underwent SBRT at a large university-affiliated oncological center in Barcelona, Spain. Variables related to the patient profile, tumor, oligometastatic disease, and treatment were evaluated. RESULTS: A total of 327 metastatic tumors were treated with SBRT. In 65.5% of cases, metachronous tumors were diagnosed at least 1 year after diagnosis of the primary tumor. The median age of the patients was 73.9 years and 66.5% were males. The median follow-up was 37.5 months. The most common primary tumors were lung and colorectal cancer, with lung and bone as the most commonly treated metastatic sites. Ninety-three percent of patients showed a Karnofsky score (KPS) between 80 and 100. Adenocarcinoma was the most common histological type. The median overall survival was 53.4 months, with 1-, 2- and 5-year survival rates of 90.5%, 73.9% and 43.4%, respectively. Overall survival rates of breast (67.6 months, 95% CI 56.4-78.9), urological (63.3 months, 95% CI 55.8-70.8), and colorectal (50.8 months, 95% CI 44.2-57.4) tumors were higher as compared with other malignancies (20 months, 95% CI 11.2-28.8 months) (p < 0.001). Patients with Karnofsky score (KPS) of 90 and 100 showed a significantly better survival than those with impaired performance status (p = 0.001). CONCLUSION: SBRT appears to be well tolerated and safe approach in oligometastatic patients. Patients with good performance status and with primary breast, urological and colorectal cancer have higher OS compared with other malignancies. More studies are necessary to evaluate the prognostic factors in oligometastatic disease (OMD) in order to select patients who could benefit more from this therapeutic approach.
Assuntos
Neoplasias Colorretais , Neoplasias Pulmonares , Segunda Neoplasia Primária , Radiocirurgia , Masculino , Humanos , Idoso , Feminino , Resultado do Tratamento , Prognóstico , Radiocirurgia/efeitos adversos , Segunda Neoplasia Primária/etiologia , Neoplasias Colorretais/patologia , Estudos Retrospectivos , Neoplasias Pulmonares/patologiaRESUMO
BACKGROUND: Emergency department nurses are continually exposed to distressing experiences that can lead to burnout, compassion fatigue, and compassionate satisfaction, thus could affect the professional quality of life. The aim of this study was to analyse professional quality of life in hospital emergency department nurses based on perceived health, social support and a series of socio-demographic and sociooccupational variables. METHODS: This descriptive cross sectional study involved nursing professionals working at hospital emergency departments in Andalusia, Spain. Professional quality of life, perceived health, socio-demographic and occupational variables, and perceived social support were measured. A descriptive and multiple regression analysis was performed. RESULTS: A total of 253 nursing professionals participated, of which 62.5% had high levels of compassion fatigue and compassion satisfaction (45.1%). Burnout levels were medium (58.5%). Perceived health significantly influenced on compassion fatigue and burnout. Perceived social support was found to be significantly related to all three dimensions of professional quality of life, but it had the greatest influence on the occurrence of burnout. CONCLUSIONS: Emergency department nurses in public hospitals are emotionally drained. Healthcare systems must develop intervention strategies to increase the quality of life of nursing professionals, which would lead to improved patient care. The promotion of compassion is a key element.
Assuntos
Esgotamento Profissional , Fadiga de Compaixão , Estudos Transversais , Empatia , Hospitais , Humanos , Satisfação no Emprego , Qualidade de Vida , Apoio Social , Inquéritos e QuestionáriosRESUMO
In the current pandemic of COVID-19, sewage surveillance of SARS-CoV-2 genome has been used to complement viral epidemiology in different countries. The aim of this work was to introduce and evaluate this wastewater-based tool in the metropolitan region of Buenos Aires, Argentina. As a pilot study, surveillance of SARS-CoV-2 in wastewater from three districts of this area was performed for more than nine months from June 2020 to April 2021. Viruses present in the samples were concentrated using polyethylene glycol precipitation and quantified using RT-qPCR CDC N1 assay. Virus recovery for SARS-CoV-2 and a potential surrogate, bovine coronavirus Mebus strain, that shares the Betacoronavirus genus and structural characteristics with SARS-CoV-2, were evaluated after concentration and detection procedures. Recovery of both viruses did not differ significantly, with a median for SARS-CoV-2 and BCoV of 0.085 (95% CI: 0.021-0.179) and 0.262 (95% CI: 1.18 × 10-5-0.564) respectively. The concentration of SARS-CoV-2 genome in wastewater ranged from 10 -1 to 10 3 cg/ml, depending on the wastewater treatment plant, type of collection site, viral recovery of the concentration method and the epidemiological situation of the outbreaks. Significant correlations were observed between SARS-CoV-2 concentration in wastewater and reported clinical cases, reinforcing the utility of this approach to monitor the epidemiological status of populations.
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COVID-19 , Águas Residuárias , Animais , Argentina/epidemiologia , Bovinos , Humanos , Projetos Piloto , SARS-CoV-2RESUMO
Fresh vegetables and shellfish are prone to microbial contamination through irrigation or breeding with sewage-polluted waters, as well as by infected food handlers. In this work, we studied the presence of human and bovine polyomaviruses and human norovirus in fresh lettuces, strawberries and oysters produced in Buenos Aires province, Argentina. In oysters, we also investigated F-specific RNA bacteriophages, indicator Escherichia coli (E. coli) and pathogen bacteria of concern (Salmonella spp., Vibrio spp.). Within vegetables, we found viral contamination of human origin given the presence of human-associated polyomaviruses -MCPyV, HPyV6, JCPyV, and SV40- in lettuce and strawberry samples (16 and 10%, respectively), probably coming from irrigation waters and food handling. Among oysters, human (MCPyV, 4.2%) and bovine (BPyV1, 8.4%) polyomaviruses were detected even with low counts of E. coli. Bacteriophages (n = 3) and Salmonella spp. (n = 1) were also found, while Vibrio spp. was not detected. These results may indicate that the contamination in oysters comes from human and animal excreta, probably present in breeding waters. Norovirus was not detected in any food sample. To our knowledge, this is the first description of SV40 in lettuces and MCPyV and BPyV1 in oysters. The detection of different viral contaminants encourages further studies to evaluate the need for including viral indicators in microbiological standards. The identification of possible sources and routes of contamination using viral markers during routine microbiological controls, such as the polyomaviruses used in this work, would be useful to focus attention on the most hazardous stages of the food production chain.
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Norovirus , Ostreidae , Animais , Argentina , Bovinos , Escherichia coli , Contaminação de Alimentos/análise , Humanos , VerdurasRESUMO
A reservoir of antibiotic resistance genes (ARGs) is present in pathogenic, commensal, and environmental bacteria as well as in mobile genetic elements, including bacteriophages. Wastewater treatment plants (WWTPs) are considered hotspots for the spread of ARGs. The aim of this work was to analyze the diversity of the highly prevalent ARGs blaCTX-M and blaTEM in bacterial and bacteriophage fractions associated with human and animal environments through the study of urban waste and animal residues discharged into WWTPs to provide information about the composition and maintenance of the current resistome in Buenos Aires, Argentina. The results showed that a putative extended-spectrum variant of the blaTEM gene was the most frequently detected, with blaTEM-116 being the most prevalent, while a recently described type, blaTEM-229, was also found. In the bacteriophage fraction, we detected blaCTX-M genes from four out of the five clusters described. The detection of blaCTX- M-9-like and blaCTX-M-25-like genes was unexpected based on surveys of the ARGs from clinical pathogens circulating regionally. The finding of divergent blaCTX-M sequences associated with previously reported environmental genes argues in favor of the natural environment as a reservoir of resistance genes. ARGs were detected in bacteriophages as frequently as in bacterial communities, and furthermore, the blaCTX-M genes were more diverse in the bacteriophage fraction. Bacteriophages might therefore play a role in the spread of ARGs in the environment, but they might also be used as "reporters" for monitoring circulating ARGs.
Assuntos
Bacteriófagos/genética , Águas Residuárias/virologia , beta-Lactamases/genética , Animais , Argentina , Bactérias/genética , Resistência Microbiana a Medicamentos/genética , Genes Bacterianos/genética , Genes Virais/genética , Variação Genética , Humanos , Filogenia , Águas Residuárias/microbiologia , beta-Lactamases/classificaçãoRESUMO
Companies are increasingly aware of their role with regard to social responsibility in its three pillars: economic, social and environmental, with their different stakeholders. Facing the dilemma of choosing the model of social responsibility they should adopt, taking care of their organizational culture and their employees, with a global vision that the business world requires. However, it is not an easy task for small and medium enterprises, mainly because of their economic shortcomings in human resources and knowledge of how to be a socially responsible company. But they are aware that Corporate Social Responsibility (CSR) is an opportunity for development and differentiation in the market. Therefore, the objective of this research is to build, identify and validate a model of Social Responsibility in small and medium enterprises in Guanajuato, Mexico (CSRSMEs), on a sample of 226 SMEs, using as a basis the methodology of the international standard of Ethical and Socially Responsible Management System (SGE21). A quantitative approach was used and, a descriptive analysis, exploratory factor analysis and the structural equation modeling was applied. The results determine that the most relevant variables for being socially responsible are human capital, clients, supply chain, social environment and impact on the community, and organizational governance: Legality and Management System. It is drawn from this work that the flexibility of the so-called Ethical and Socially Responsible Management System has the empirical foundations needed. That is, from the perspective of the company's management to consider the CSRSMEs model an opportunity to adopt and evaluate the areas of social responsibility management of any business structure in the SMEs in Mexico.
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Comércio , Cultura Organizacional , Responsabilidade Social , Pesquisa Empírica , México , Modelos EstruturaisRESUMO
Enteric viruses are pathogens associated with food- and waterborne outbreaks. The recovery of viruses from food or water samples is affected by the procedures applied to detect and concentrate them. The incorporation of an internal process control virus to the analyses allows monitoring the performance of the methodology. The aim of this study was to produce a recombinant adenovirus (rAdV) and apply it together with bacteriophage PP7 as process controls. The rAdV carries a DNA construction in its genome to differentiate it from wild-type adenovirus by qPCR. The stability of both control viruses was evaluated at different pH conditions. The rAdV was stable at pH 3, 7, and 10 for 18 h. PP7 infectious particles were stable at pH 7 and showed a 2.14 log reduction at pH 10 and total decay at pH 3 after 18 h. Three virus concentration methods were evaluated: hollow-fiber tap water ultrafiltration, wastewater ultracentrifugation, and elution-PEG precipitation from lettuce. Total and infectious viruses were quantified and their recoveries were calculated. Virus recovery for rAdV and PP7 by ultrafiltration showed a wide range (2.10-84.42 and 13.54-84.62%, respectively), whereas that by ultracentrifugation was 5.05-13.71 and 6.98-13.27%, respectively. The performance of ultracentrifugation to concentrate norovirus and enteroviruses present in sewage was not significantly different to the recovery of control viruses. For detection of viruses from lettuce, genomic copies of PP7 were significantly more highly recovered than adenovirus (14.74-18.82 and 0.00-3.44%, respectively). The recovery of infectious virus particles was significantly affected during sewage ultracentrifugation and concentration from lettuce. The simultaneous use of virus controls with dissimilar characteristics and behaviors might resemble different enteric viruses.
Assuntos
Microbiologia de Alimentos , Vírus/isolamento & purificação , Microbiologia da Água , Adenoviridae/genética , Adenoviridae/fisiologia , Enterovirus/genética , Enterovirus/isolamento & purificação , Concentração de Íons de Hidrogênio , Lactuca/virologia , Levivirus/genética , Levivirus/isolamento & purificação , Norovirus/genética , Norovirus/isolamento & purificação , Fagos de Pseudomonas/genética , Fagos de Pseudomonas/fisiologia , Reação em Cadeia da Polimerase em Tempo Real , Esgotos/virologia , Ultracentrifugação , Ultrafiltração , Vírus/genéticaRESUMO
New human polyomaviruses have been recently described. The aim of this work was to detect and characterize human polyomaviruses circulating in Argentina by recovering viruses from environmental and sewage samples and evaluating their potential role as viral indicators of human waste contamination. Analysis was performed in a wider context including viruses from clinical samples from an immunocompromised population. River water and sewage samples were analyzed as a strategy to study the molecular epidemiology of viruses excreted by millions of people. Samples belonged to the Matanza-Riachuelo River (2005-2006: n=25 and 2012: n=20) and sewage from Buenos Aires city and suburbs (2011 and 2013: n=24). Viral detection was performed by PCR and the amplified viral genomes were characterized by phylogenetic analysis. Polyomaviruses were detected in 95.8% of sewage samples, identifying BKPyV (87.5%), JCPyV (83.3%), MCPyV (8.3%) and HPyV6 (8.3%). Besides, one sample collected in 2009 resulted positive for HPyV7. In 2005-2006, polyomaviruses were detected in 84.0% of river water samples, with the highest detection for MCPyV (52.0%), followed by BKPyV (44.0%), JCPyV (20.0%) and MWPyV (4.0%). In 2012, polyomaviruses were detected in 85.0% of river samples, finding JCPyV (85.0%), BKPyV (75.0%), MCPyV (25.0%) and HPyV6 (25.0%). Also, polyomaviruses, including JCPyV, BKPyV and MCPyV, were detected in 63.2% of urine samples from patients infected with HIV (n=19). Characterization indicated the coexistence of different genotypes and variants for each virus, particularly in sewage. MCPyV sequences (the only sequences from Argentina) formed a monophyletic group with the single sequence available for South America (French Guiana). The high level of detection and viral diversity found by environmental surveillance, which involved the characterization of viruses not previously described in South America, reinforces the usefulness of this approach to monitor viral contamination and describe the viral epidemiology in the general population.
Assuntos
Microbiologia Ambiental , Monitoramento Ambiental , Polyomavirus/genética , Argentina , Humanos , Filogenia , Polyomavirus/classificação , Rios/virologia , Esgotos/virologiaRESUMO
The aim of this work was to analyse the influence of overlapping genes on the evolution of hepatitis B virus (HBV). A differential evolutionary behaviour among genetic regions and clinical status was found. Dissimilar levels of conservation of the different protein regions could derive from alternative mechanisms to maintain functionality. We propose that, in overlapping regions, selective constraints on one of the genes could drive the substitution process. This would allow protein conservation in one gene by synonymous substitutions while mechanisms of tolerance to the change operate in the overlapping gene (e.g. usage of amino acids with high-degeneracy codons, differential codon usage and replacement by physicochemically similar amino acids). In addition, differential selection pressure according to the HBeAg status was found in all genes, suggesting that the immune response could be one of the factors that would constrain viral replication by interacting with different HBV proteins during the HBeAg(-) stage.
Assuntos
Homologia de Genes , Genes Virais , Vírus da Hepatite B/genética , Evolução Molecular , Antígenos E da Hepatite B/genética , Antígenos E da Hepatite B/imunologia , Vírus da Hepatite B/imunologia , Humanos , Mutação , Seleção GenéticaRESUMO
Enteric viruses monitoring in surface waters requires the concentration of viruses before detection assays. The aim of this study was to evaluate different methods in terms of recovery efficiencies of bacteriophage PP7 of Pseudomonas aeruginosa, measured by real-time PCR, using it as a viral control process in water analysis. Different nucleic acid extraction methods (silica-guanidinium thiocyanate, a commercial kit (Qiagen Viral RNA Kit) and phenol-chloroform with alcohol precipitation) exhibited very low recovery efficiencies (0.08-4.18 %), being the most efficient the commercial kit used for subsequent experiments. To evaluate the efficiency of three concentration methods, PBS (as model for clean water) and water samples from rivers were seeded to reach high (HC, 10(6) pfu ml(-1)) and low concentrations (LC, 10(4) pfu ml(-1)) of PP7. Tangential ultrafiltration proved to be more efficient (50.36 ± 12.91, 17.21 ± 9.22 and 12.58 ± 2.35 % for HC in PBS and two river samples, respectively) than adsorption-elution with negatively charged membranes (1.00 ± 1.34, 2.79 ± 2.62 and 0.05 ± 0.08 % for HC in PBS and two river samples, respectively) and polyethylene glycol precipitation (15.95 ± 7.43, 4.01 ± 1.12 and 3.91 ± 0.54 %, for HC in PBS and two river samples, respectively), being 3.2-50.4 times more efficient than the others for PBS and 2.7-252 times for river samples. Efficiencies also depended on the initial virus concentration and aqueous matrixes composition. In consequence, the incorporation of an internal standard like PP7 along the process is useful as a control of the water concentration procedure, the nucleic acid extraction, the presence of inhibitors and the variability of the recovery among replicas, and for the calculation of the sample limit of detection. Thus, the use of a process control, as presented here, is crucial for the accurate quantification of viral contamination.
Assuntos
Monitoramento Ambiental/métodos , Levivirus/crescimento & desenvolvimento , Pseudomonas aeruginosa/virologia , Rios/microbiologia , Microbiologia da Água , Adsorção , Levivirus/isolamento & purificação , Limite de Detecção , Pseudomonas aeruginosa/crescimento & desenvolvimento , UltrafiltraçãoRESUMO
A proposta desenvolvida a partir dos profissionais técnicos do Centro de Saúde El Progresso, consiste em um início de um processo de intervenção e participação da comunidade para enfrentar os problemas e contribuir com a melhoria da qualidade de vida da população da área de abrangência, contando com serviços, recursos existentes e o apoio das instituições. Com estas reflexões se promoveu o Processo Comunitário da Margem Direita do Rio Guadiana descreveremos ao longo deste relato. A administração sanitária assume a formação da assistente social da equipe em torno das experiências comunitárias assessoradas pelo consultor externo contratado pelo governo, Dr Marco Marchioni, que contribuiu com a formação necessária para o desenvolvimento do processo comunitário. Para que esta coordenação evolua para uma intervenção conjunta, é necessária a realização de um Diagnóstico Comunitário que possibilite uma visão compartida, global e integral da comunidade. Esta primeira etapa do Processo Comunitário desenvolveu o Diagnóstico com todas as pessoas envolvidas e divulgou os resultados a toda a comunidade. Seguindo o esquema da análise DAFO, se pode dizer que a Margem Direita do Guadiana tem umas debilidades e umas fortalezas (análise interna) que se aproximam uma série de ameaças e de oportunidades (análise externa). Para conseguir participação comunitária e gestão participativa efetiva há que ter persistência e aproveitar as oportunidades. O tecido associativo da Margem direita do Rio Guadiana e o Diagnóstico da área servem para unir as pessoas em um objetivo comum e diminuir a dicotomização existente, fazendo com que as mudanças sejam positivas e que as ameaças se transformem em oportunidades.
The proposal developed from the professional technicians from the Center for Health Progress, consists of a beginning of a process of intervention and participation of the community to address problems and contribute to improving the quality of life of people in the area of coverage, with services, resources and support of existing institutions. With these thoughts are promoted Procedure Committee of the right margin of the Guadiana river describe throughout this article. The administration takes the training of health social worker team's experiences around the community advised by March Marchioni, who helped with the training necessary for the development of the Community procedure. For this coordination to evolve a joint Intervention, it is necessary to carry out a Community Diagnosis enabling a shared vision, comprehensive and integrated community. This first stage of the process developed the Community Diagnosis with everyone involved and reported the results to the entire community. Following the pattern of analysis Dafoe, we can say that the right margin of the Guadiana river has some strengths and some weaknesses (internal analysis) approaching a series of threats and opportunities (external review). To achieve community participation and effective participatory management should be taken persistence and seize the opportunities. The fabric of voluntary right margin of Guadiana River Diagnóstico of area and serve to unite people in a common goal and to reduce existing dichotomization, so that the changes are positive and that threats become opportunities.
Assuntos
Participação da Comunidade , Qualidade de Vida , Centros de Saúde , Serviços de Saúde Comunitária , Medicina de Família e Comunidade , Recursos em SaúdeRESUMO
PURPOSE: We retrospectively reviewed our Institution's database to investigate the outcome and impact of combined radiochemotherapy (RT/CT; concomitant or in sequence) in localised small-cell lung cancer (L-SCLC). MATERIAL AND METHODS: Between January 1995 to November 1999, 79 patients with L-SCLC received combined RT/CT at our Institution. RT was delivered concurrently or sequentially following the CT. Patients with treatment response received additional prophylactic cranial irradiation (PCI). RESULTS: Of the patients treated, 54% had received concurrent CT/RT compared to 46% receiving RT following the CT. PCI was administered to 80% of the patients. Complete response was observed in 66% of patients. With a median follow up of 30 months, median overall survival was 15.9 months; 14.3 months for patients who received RT following CT and 21.6 months for those receiving concurrent CT/RT. The type of schedule of combined radiochemotherapy was an independent prognostic factor for survival free of local recurrence, as was additional PCI for distant metastasis-free survival. CONCLUSIONS: Our results are similar to those reported previously in the literature. The main point of interest is that our patients were non-selected. We strongly support the use of concurrent CT/RT so as to achieve results comparable to the best in the literature.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Carcinoma de Células Pequenas/terapia , Neoplasias Pulmonares/terapia , Adulto , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Carcinoma de Células Pequenas/tratamento farmacológico , Carcinoma de Células Pequenas/radioterapia , Cisplatino/administração & dosagem , Cisplatino/efeitos adversos , Terapia Combinada , Irradiação Craniana , Intervalo Livre de Doença , Esofagite/etiologia , Etoposídeo/administração & dosagem , Etoposídeo/efeitos adversos , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/radioterapia , Masculino , Pessoa de Meia-Idade , Neutropenia/etiologia , Pneumonite por Radiação/etiologia , Radioterapia/efeitos adversos , Indução de Remissão , Estudos Retrospectivos , Análise de Sobrevida , Resultado do TratamentoRESUMO
We evaluated the effects of an elevated [CO2] on photosynthesis and growth of cassava plants grown in open-top chambers with an adequate supply of water and N and a sufficient rooting volume. Cassava plants (Manihot esculenta Crantz. cv. Motilona) showed higher photosynthetic rates (Pn) when grown and measured at elevated [CO2] (680 µmol mol-1) than when grown and measured at ambient [CO2] (480 µmol mol-1). No downregulation of photosynthesis due to elevated [CO2] was found, since carboxylation efficiency increased after 220 d in spite of a decrease in leaf soluble protein, Rubisco, and leaf N content. Soluble sugar and starch contents decreased with time under elevated [CO2], the decrease in starch content coinciding with the beginning of the increase in root mass. Canopy Pn by leaf area decreased with time under elevated [CO2] but, when canopy Pn was expressed by ground area, higher and constant rates were observed, suggesting a higher productivity in plants grown at elevated [CO2]. The absence of differences between growth [CO2] in root : shoot ratio observed suggests that elevated [CO2], while causing increases in the shoot as well as the root, did not affect the pattern of biomass allocation. Acclimation responses of gas exchange parameters changed during the experiment. The absence of downregulation of photosynthesis was associated with a decrease in leaf sugar and starch contents of plants grown at elevated [CO2], which suggests a favourable source/sink relationship.
RESUMO
La gran cantidad de información acerca de los efectos de un incremento experimental de la [CO²] de cultivo sobre la fisiología de plantas de zonas templadas contrasta con la reducida información disponible para plantas tropicales. En atención a ello, se estudiaron las respuestas fotosintéticas a [CO²] elevadas de plantas que crecen en Venezuela. Se cultivaron plantas de cuatro especies xerófitas bajo una [CO²] elevada, para elucidar el efecto de ésta sobre la fotosíntesis y el uso de agua de especies que normalmente enfrentan déficit hídricos. La fotosíntesis aumentó alrededor de 3,5 veces y la [CO²] elevada retrasó la disminución de la tasa fotosintética en sequía. Dado que en muchos estudios se ha encontrado que el estímulo inicial de la fotosíntesis por una [CO²] elevada desaparace en el tiempo debido a las limitaciones de sumidero de asimilados, hicimos un estudio del efecto de la [CO²] elevada sobre la fotosíntesis de plantas de yuca cultivadas sin limitaciones de suelo, encontrando que la tasa fotosintética no disminuyó durante todo el ciclo de cultivo. La existencia de un sumidero grande (la raiz) unida a una gran disponibilidad de sustrato, permitió que la estimulación de la tasa fotosintética por la [CO²] elevada continuara en el tiempo. Se evaluó el efecto de [CO²] muy altas sobre la fotosíntesis de plantas silvestres que crecen alrededor de emanaciones naturales, encontrándose que tales concentraciones no sólo no inhiben la tasa fotosintética, sino que la promueven muy por encima de la de los controles