scholarly journals Effect of Species Invasion on Transport of Solutes at Different Levels of Soft Sediment Macrofauna Diversity: Results from an Experimental Approach

Water ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1544
Author(s):  
Daunys ◽  
Forster ◽  
Schiedek ◽  
Olenin ◽  
Zettler
Keyword(s):  
Native Species ◽  
Laboratory Experiments ◽  
Experimental Approach ◽  
Tracer Transport ◽  
Hediste Diversicolor ◽  
Ventilation Strategies ◽  
Reactive Solutes ◽  
Benthic Pelagic Coupling ◽  
Different Levels ◽  
Macrofauna Community

Different irrigation or ventilation strategies by macrofauna may provide a competitive advantage to tolerant species invading impacted benthic systems and alter benthic-pelagic coupling. To comparatively analyze the effects of an exotic and a native polychaete burrower on sediment-water exchanges, two laboratory experiments were performed. In the first experiment, the invasive spionid polychaete Marenzelleria neglecta was added to defaunated sediments and fluxes of the inert tracer (bromide, Br−) were measured to quantify the effects of irrigation by the worm on the tracer transport. In the second experiment, M. neglecta or the native polychaete Hediste diversicolor were introduced to a relatively diverse Baltic soft-bottom macrofauna community. The effect of species on fluxes of reactive solutes (ammonium, NH4+, and phosphate, PO43−) and transport rates of Br− was estimated. The results indicate different invasion effects depending on the characteristics of the recipient habitat. In defaunated sediments, a single specimen of M. neglecta significantly enhanced originally low solute exchange rates. Total tracer flux was significantly enhanced over diffusive flux by a factor of 1.6 ± 0.14 (n = 3). In natural sediments, on the other hand, the addition of either M. neglecta or H. diversicolor had no statistically significant effects on benthic fluxes. Tracer flux estimates between control and treatment incubations differed by less than 10% on average, and both reactive solutes tended to increase by 10 to 40% after additions. One specimen of M. neglecta in cores with defaunated sediment generated approximately 20% of the tracer flux produced by the relatively diverse macrofauna community. Estimated net tracer fluxes in two experiments corresponded well with the number of adult polychaetes found in sediments (r2 = 0.73, p = 0.005, n = 12). The invasive M. neglecta produced a small effect on fluxes in biodiverse sediments, comparable to those of H. diversicolor, but it may deeply alter porewater chemistry in azoic sediment. As M. neglecta tolerates chemically reduced and sulphidic conditions, its bioirigation may favor sediment reoxidation and ultimately the recolonization by less tolerant, native species.

scholarly journals Management of Intraoperative Mechanical Ventilation to Prevent Postoperative Complications after General Anesthesia: A Narrative Review

2021 ◽  
Vol 10 (12) ◽  
pp. 2656
Author(s):  
Alberto Fogagnolo ◽  
Federica Montanaro ◽  
Lou’i Al-Husinat ◽  
Cecilia Turrini ◽  
Michela Rauseo ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Tidal Volume ◽  
Pulmonary Complications ◽  
Point Of View ◽  
Whole Body ◽  
Positive End Expiratory Pressure ◽  
Ventilation Strategies ◽  
Harmful Effects ◽  
Ventilation Induced Lung Injury ◽  
Different Levels

Mechanical ventilation (MV) is still necessary in many surgical procedures; nonetheless, intraoperative MV is not free from harmful effects. Protective ventilation strategies, which include the combination of low tidal volume and adequate positive end expiratory pressure (PEEP) levels, are usually adopted to minimize the ventilation-induced lung injury and to avoid post-operative pulmonary complications (PPCs). Even so, volutrauma and atelectrauma may co-exist at different levels of tidal volume and PEEP, and therefore, the physiological response to the MV settings should be monitored in each patient. A personalized perioperative approach is gaining relevance in the field of intraoperative MV; in particular, many efforts have been made to individualize PEEP, giving more emphasis on physiological and functional status to the whole body. In this review, we summarized the latest findings about the optimization of PEEP and intraoperative MV in different surgical settings. Starting from a physiological point of view, we described how to approach the individualized MV and monitor the effects of MV on lung function.

scholarly journals Initial development and gas exchange of Talisia subalbens (Mart.) Radlk. under different shading conditions

2011 ◽  
Vol 35 (1) ◽  
pp. 61-67 ◽  
Author(s):  
Fernanda Carlota Nery ◽  
Hilton Morbeck de Oliveira ◽  
Amauri Alves de Alvarenga ◽  
Sara Dousseau ◽  
Evaristo Mauro de Castro ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Native Species ◽  
Cultivated Plants ◽  
Initial Growth ◽  
Initial Development ◽  
Basal Diameter ◽  
Shoot Ratio ◽  
Root Shoot Ratio ◽  
Significant Difference ◽  
Different Levels

Ecophysiological studies under semi-controlled conditions in nurseries and greenhouses are essential to enable the use of native species to recover degraded areas and for commercial planting. Talisia subalbens (Mart) Radlk, 'cascudo', is a native fruiting species of the Cerrado on the verge of extinction. The ecophysiological performance of this species was evaluated in nursery conditions under different levels of shading (full sunshine, 30%, 50% and 70%). Initial growth, biomass allocation, gas exchange and chlorophyll content of the plants were analyzed. Full sunshine cultivated plants showed a higher accumulation of total, shoot, and root dry biomass. There was no significant difference in the root/shoot ratio among the treatments. Seedlings cultivated under full sunshine and 30% shading showed higher values for height, basal diameter, and leaf area. Differences in stomata conductance and photosynthesis rate were not observed among the different shading levels. Plants cultivated under 70% of shading had higher contents of chlorophyll a, b, and total. During the initial phase with higher levels of radiation were fundamental for the development of T. subalbens seedlings.

Introduction: categorization, cleverness and consciousness

1985 ◽  
Vol 308 (1135) ◽  
pp. 3-19 ◽  
Keyword(s):  
Experimental Approach ◽  
Conscious Awareness ◽  
Object Identity ◽  
Complex Environment ◽  
Basic Form ◽  
History Of ◽  
Categorical Knowledge ◽  
The Subject ◽  
The One ◽  
Different Levels

Various recurring themes in the history of the subject are reviewed. In the context of adaptation to a complex environment, one precondition for survival must be a capacity for object identity, which may be the most basic form of categorization. Evidence will be presented that suggests that the capacity is not learned. In considering learned associations among categorized items, a distinction is made between reflexive and reflective processes: that is between those associations in which a cue or signal provides an unambiguous route to the response, no matter how complex that route may be, in contrast to those in which learned information must be ordered and reordered ‘in thought'. An example of one experimental approach to the latter is provided. Finally, the problem of conscious awareness is considered in terms of stored categorical knowledge and associations, on the one hand, and a system that monitors them, on the other. Neurological evidence of disconnections between these different levels is reviewed.

Immersed in the source text

Babel ◽  
2019 ◽  
Vol 65 (2) ◽  
pp. 264-285
Author(s):  
Beatriz Naranjo Sánchez
Keyword(s):  
Pilot Study ◽  
Experimental Approach ◽  
Literary Translation ◽  
Emotional Engagement ◽  
Source Text ◽  
Empirical Results ◽  
Narrative Transportation ◽  
Translation Quality ◽  
The Impact ◽  
Different Levels

Abstract This study aims at exploring the phenomenon of psychological transportation in translation from an experimental approach. Firstly, we investigate whether the emotions depicted in source texts may influence the level of transportation experienced by translators. Secondly, we try to determine whether different levels of transportation in the texts can make a difference in terms of translation performance. Based on previous work about narrative transportation in products of fiction, as well as the phenomenon known as the “paradox of pleasurable sadness”, we depart from the hypothesis that sad texts lead to a higher degree of psychological transportation than happy texts (H1). Taking into account previous theories and empirical results about the benefits of visualization and emotional engagement in translation, we also predict that highly-transported participants will render higher-quality (H2) and more creative translations (H3) than low-transported participants. For this purpose, a pilot study was conducted consisting of two literary translation tasks with opposing-valence texts (happy vs. sad). Lack of statistically significant differences for our hypothesis suggests that some adjustments in the methodology would be needed to achieve conclusive results; however, we believe that further research on the impact of transportation in translation quality and creativity is still worthwhile.

scholarly journals The genetic and social contributions to sex differences in lifespan in Drosophila serrata

2021 ◽  
Author(s):  
Vikram P. Narayan ◽  
Alastair J. Wilson ◽  
Stephen F. Chenoweth
Keyword(s):  
Sex Differences ◽  
Experimental Approach ◽  
Social Background ◽  
Social Effects ◽  
Mating Status ◽  
X Chromosomes ◽  
Deleterious Alleles ◽  
Social Contributions ◽  
Drosophila Serrata ◽  
Different Levels

AbstractSex differences in lifespan remain an intriguing puzzle for evolutionary biologists. A possible explanation for lower lifespan in males is the unconditional expression of recessive deleterious alleles in heterogametic X chromosomes in males (the unguarded X hypothesis). Empirical evidence, however, has yielded controversial results that can be attributed to differences in both genetic and social background. Here, we test the unguarded X hypothesis in Drosophila serrata using a factorial design to quantify the effects of genotype, sex, social environment, and their interactions on phenotypic variation for lifespan. Using an experimental approach, we manipulated two inbred laboratory genotypes and their reciprocal F1s, while controlling for different levels of density and mating status to account for any potential social effects. Our results also show subtle but significant genotype dependent effects for both density and mating, but ultimately find the unguarded X hypothesis insufficient to fully explain sexual dimorphism in D. serrata lifespan.

Slope and Fuel Load Effects on Fire Behavior: Laboratory Experiments in Pine Needles Fuel Beds

1995 ◽  
Vol 5 (3) ◽  
pp. 153 ◽  
Author(s):  
JL Dupuy
Keyword(s):  
Laboratory Experiments ◽  
Pinus Halepensis ◽  
Fire Behavior ◽  
Fuel Load ◽  
Fire Behaviour ◽  
Rate Of Spread ◽  
Load Effects ◽  
Heat Transfers ◽  
Different Levels ◽  
Fire Experiments

Laboratory fire experiments were conducted in both Pinus pinaster and Pinus halepensis litters in order to investigate the effect of slope on fire behaviour for different levels of fuel load. Simulated slopes ranged between -30 degrees and +30 degrees. The results are reported in terms of rate of spread and rate of mass loss when observed fire was quasi-steady. Upslope fires were observed, on the present devices, to be unsteady, and their flame to be three-dimensionnal, when slope and fuel load exceeded certain limits. The heat transfers involved in the explanation of the observed behaviours are discussed, especially on the base of the quite different results obtained in the two tested fuel. beds.

Electoral incentives for cross-ethnic voting: evidence from a natural experiment

2019 ◽  
Vol 11 (2) ◽  
pp. 197-212 ◽  
Author(s):  
Nenad Stojanović ◽  
Oliver Strijbis
Keyword(s):  
Empirical Analysis ◽  
Laboratory Experiments ◽  
Natural Experiment ◽  
Proportional Representation ◽  
Proportional Systems ◽  
Electoral Incentives ◽  
Ethnic Parties ◽  
Swiss Canton ◽  
Linguistic Groups ◽  
Different Levels

AbstractProspects for democracy in multi-ethnic societies are generally more promising if elections are not mere ethnic censuses, in which people vote predominantly for co-ethnic parties and candidates. But what institutions facilitate or hinder ethnic voting? Unlike past studies, this article explores ethnic voting by conducting a natural experiment (rather than surveys or laboratory experiments). It examines the case of Fribourg, a bilingual (French/German) Swiss canton where elections at different levels of government, within the same electoral district, are held under both majoritarian and proportional systems. Coupled with the high territorial homogeneity of the linguistic groups, this unique setting allows us to conduct a robust empirical analysis of voter behaviour. We find that cross-ethnic voting is significantly more frequent in multi-member majoritarian elections than in list-PR elections or in two-member majoritarian elections. Our results yield qualified support to the centripetalist approach to electoral design in multi-ethnic societies, that favours majoritarian systems, rather than to the consociational school that advocates proportional representation.

scholarly journals EFICIÊNCIA DE TRATAMENTOS SILVICULTURAIS POR ANELAMENTO NA FLORESTA DO JARI, AMAPÁ

FLORESTA ◽  
2012 ◽  
Vol 42 (2) ◽  
pp. 315 ◽  
Author(s):  
Celso Paulo de Azevedo ◽  
José Natalino Macedo Silva ◽  
Cintia Rodrigues de Souza ◽  
Carlos Roberto Sanquetta
Keyword(s):  
Mortality Rate ◽  
Native Species ◽  
Basal Area ◽  
Important Variation ◽  
Area Reduction ◽  
Silvicultural Treatments ◽  
Silvicultural Treatment ◽  
Dead Trees ◽  
Different Levels ◽  
Diameter Classes

 O anelamento é um tratamento silvicultural aplicado nas florestas tropicais com o objetivo de manter ou até aumentar a produtividade das espécies exploradas comercialmente para o próximo ciclo de corte. Neste trabalho, analisou-se o efeito de diferentes níveis de exploração e tratamentos silviculturais sobre a dinâmica da floresta remanescente na região do Jari/AP. O tratamento silvicultural foi realizado em 1994, aplicando-se dois tipos de desbaste: desbaste sistemático, com intensidades de redução da área basal original de 30% e 50% e o desbaste seletivo (anelamento com entalhes e aplicação de arboricida). Na aplicação do tratamento, foram aneladas em média 18,3 árvores.ha-1, 2,1 m2.ha-1 de área basal e 25,1 m3.ha-1 de volume, com total de 495 indivíduos anelados (de 93 espécies). A quantidade de árvores mortas em consequência do anelamento variou consideravelmente entre os tratamentos. De maneira geral, o anelamento com a aplicação do arboricida mostrou maior efeito em função da espécie do que com o tamanho das árvores. Espécies com troncos sulcados apresentaram baixa mortalidade. Árvores com diâmetro inferior a 50 cm apresentaram mortalidade de 61 a 90%. Nas classes diamétricas superiores, a taxa de mortalidade foi semelhante, em torno de 69 a 100%.Palavras-chave: Espécies nativas; tratamentos silviculturais; exploração florestal; Amazônia. AbstractEfficiency of silvicultural treatments by girdling in the Jari Forest, Amapá. The girdling is a silvicultural treatment applied in tropical forests in order to maintain or even increase the productivity of commercially exploited species to the next cutting cycle. In this research we analyzed effects of different levels of exploitation and silvicultural treatments on the dynamics of remaining forest in the Jari region/AP. The silvicultural treatment was improved in 1994 and applied to two types of thinning: systematic thinning, with intensities of original basal area reduction of 30% and 50% and selective thinning (with girdling slots and applying arboricida). In the application of treatment it were ringed on average 18.3 trees.ha-1, 2,1 m2.ha-1 of basal area and 25.1 m3.ha-1 of volume, total of 495 treated individuals (93 species). The amount of dead trees as a result of girdling had important variation between treatments. In general, the girdling with application of arboricida presented greater effect in relation to the species than to trees sizes. Species with furrowed trunks presented low mortality. Trees with less than 50 cm of diameter had a mortality rate of 61 to 90 percent. In superior diameter classes the mortality rate was similar, around 69 to 100 percent.Keywords: Native species; silvicultural treatments; forest exploration; Amazonia. 

scholarly journals Impact of dissolved lignin in oxygen delignification and chlorine dioxide stages

TAPPI Journal ◽  
2016 ◽  
Vol 15 (3) ◽  
pp. 167-174 ◽  
Author(s):  
Caroline Wilke ◽  
Niclas Andersson ◽  
Rick Van Fleet ◽  
Akhlesh Mathur ◽  
Ulf Germgard
Keyword(s):  
Chlorine Dioxide ◽  
Laboratory Experiments ◽  
Feedforward Control ◽  
Lignin Content ◽  
Pulp Mill ◽  
Kappa Number ◽  
Oxygen Delignification ◽  
Disturbance Factor ◽  
A Minor ◽  
Different Levels

While carryover of dissolved lignin between stages in the pulp mill fiber line is a well-known problem, it is still typically seen only as a minor disturbance factor or bias in the control of oxygen (O2) delignification and bleaching stages. The present study, however, reveals that it plays a larger role than anticipated, and that it should be properly analyzed in order to correctly control the process stages. This is especially important for the O2 and D0 stages as the lignin content is still high in these positions. The results of the study show that dissolved lignin carried over between stages may have a significant impact on the bleaching chemical consumption and, indirectly, on the pulp quality. Mill investigations have shown very large variations in the dissolved lignin content in the pulp before the oxygen delignification stage and before the D0 stage that have significantly influenced the bleaching chemical demand and, subsequently, the degree of delignification. In order to develop a better understanding of the mechanisms of the dissolved lignin’s reactions, laboratory O2 and D0 experiments with controlled levels of dissolved lignin were conducted. It was anticipated that a better feedforward control could be achieved using an online dissolved lignin measurement, and results from mill trials are presented. Chlorine dioxide laboratory experiments using different levels of carryover (i.e., different dissolved lignin contents) were conducted. It was concluded that the filtrate kappa number provides a relevant measure of the bleach demand due to the dissolved lignin and that, subsequently, the combined fiber and filtrate kappa number provides an appropriate measure for optimum feedforward control of the stages. Mill results support these findings, which show that the chemical consumption is reduced significantly using the total kappa number. The post-D or post-DE kappa number feedback control can most probably be eliminated by using this technology.

scholarly journals Free Ocean CO<sub>2</sub> Enrichment (FOCE) systems: present status and future developments

2014 ◽  
Vol 11 (3) ◽  
pp. 4001-4046 ◽  
Author(s):  
J.-P. Gattuso ◽  
W. Kirkwood ◽  
J.P. Barry ◽  
E. Cox ◽  
F. Gazeau ◽  
...  
Keyword(s):  
Indirect Effects ◽  
Laboratory Experiments ◽  
Experimental Approach ◽  
Co2 Enrichment ◽  
Field Observations ◽  
Biological Communities ◽  
Precise Control ◽  
Future Developments ◽  
The Impact

Abstract. Free Ocean CO2 Enrichment (FOCE) systems are designed to assess the impact of ocean acidification on biological communities in situ for extended periods of time (weeks to months). They overcome some of the drawbacks of laboratory experiments and of field observations by enabling (1) precise control of CO2 enrichment by monitoring pH as an offset of ambient pH, (2) consideration of indirect effects such as those mediated through inter-specific relationships and food-webs, and (3) relatively long experiments with intact communities. Bringing perturbation experiments from the laboratory to the field is however extremely challenging. The goal of this paper is to provide guidelines on the general design, engineering, and sensors required to conduct FOCE experiments. Present and existing FOCE systems are briefly described and examples of data collected presented. Future developments are also addressed as it is anticipated that the next generation of FOCE systems will include, in addition to pH, options for oxygen and/or temperature control. FOCE systems should become an important experimental approach for projecting the future response of marine ecosystems to environmental change.

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