| 1. |
- Abdelgadir, Mohanad, et al.
(författare)
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Distribution of denitrifiers predicted by correlative niche modeling of changing environmental conditions and future climatic scenarios across the Baltic Sea
- 2023
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Ingår i: Ecological Informatics. - : Elsevier. - 1574-9541 .- 1878-0512. ; 78
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Tidskriftsartikel (refereegranskat)abstract
- Denitrifying microbial communities provide an important ecosystem function in aquatic systems. Yet, knowledge on predictive and modeling of these complex and changing communities is limited. The emergently challenging question of how the geographical distribution of denitrifiers responds to ongoing and future environmental change is not yet fully understood. In our study we use metadata-based correlative niche modeling to analyze the geographical distribution of selected putative denitrifiers in the genus Sphingomonas, Mycoplana, Shewanella, and Alteromonas at different predicted environmental conditions and future climatic scenarios across the Baltic Sea. Using the predictive power of an ensemble modeling approach and eight different machine-learning algorithms, habitat suitability and the distribution of the selected denitrifiers were evaluated using geophysical and bioclimatic variables, benthic conditions, and four Representative Concentration Pathway (RCP) trajectories of future global warming scenarios. All algorithms provided successful prediction capabilities both for variable importance, and for habitat suitability with Area Under the Curve (AUC) values between 0.89 and 1.00. Model findings revealed that salinity and nitrate concentrations significantly explained the variation in distribution of the selected denitrifiers. Rising temperatures of 0.8 to 1.8 °C at future RCP60–2050 trajectories are predicted to diminish or eliminate the bioclimatic suitable habitats for denitrifier distributions across the Baltic Sea. Multi-collated terrestrial and marine environmental variables contributed to the successful prediction of denitrifier distributions within the study area. The correlative niche modeling approach with high AUC values presented in the study allowed for accurate projections of the future distributions of the selected denitrifiers. The modeling approach can be used to improve our understanding of how ongoing and predicted future environmental changes may affect habitat suitability for organisms with denitrification capacity across the Baltic Sea.
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| 2. |
- Aburto, J., et al.
(författare)
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Territorial user rights for artisanal fisheries in Chile : intended and unintended outcomes
- 2013
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Ingår i: Ocean and Coastal Management. - : Elsevier BV. - 0964-5691 .- 1873-524X. ; 71, s. 284-295
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Tidskriftsartikel (refereegranskat)abstract
- Granting property property rights in fisheries is assumed to provide incentives for sustainable resource exploitation. These rights might also open other income options for fishers, including some that go beyond the original objectives intended by authorities establishing the right. The opportunity for alternative uses is especially high if the details of these rights are not clearly identified. In Chile, a de novo TURF (Territorial User Rights for Fishery) system, called Management Exploitation Areas for Benthic Resources (Areas de Manejo y Explotacion de Recursos Bentonicos-AMERB) was created to achieve sustainable exploitation of benthic resources. This study compares two small-scale fishing communities in Chile, Guayacan and Huentelauquen, representing two typical contrasting settings, regarding geographical contexts and surroundings, origin, history, location, social embeddedness, main fisheries activities as well as the motivation and the process through which they acquired their AMERB. While in Guayacan the main fishing activity outside the AMERB is the giant squid and finfish fishery, in Huentelauquen the main and traditional activity has been diving for benthic resources. The objectives to acquire their AMERBs were different in both cases. Huentelauquen applied the AMERB for their traditional activity, the fishery of Concholepas concholepas ("loco"), thus in accordance with the official objective of the AMERB. Due to reduced catches of loco, fishers also added the collection of kelps, using their AMERB to control access to the entire coast surrounding their fishing community, beyond the limits of their AMERB. In Guayacan the AMERB, applied for the management of scallops and a species of red algae, began to be used for sea squirt aquaculture. Within the framework of sustainable fisheries implied by the AMERBs, there was in both cases a clear expectation to gain new sources of income. However with time both AMERBs are being used as a tool for territorial exclusion of other fishers beyond the limits of their respective AMERBs. In Huentelauquen fishers mention mostly negative aspects about the performance of their AMERB, given the poor economic results, being unsatisfied with the AMERB system in general, because they feel that the system disrupted their traditional migration along the coast. In Guayacan, fishers mentioned mostly positive aspects for their AMERB, as it was an opportunity to add new activities. Both examples show that rights-based management approaches are very attractive; they could promote new uses or developments, whose sustainability nevertheless needs to be analyzed further. The analyzed case studies show that, contrary to how the system was developed in Chile, a more bottom-up implementation of new management arrangements may make it easier to agree on common objectives, and/or leave more freedom for fishers to adjust and arrange their livelihood. Considering the importance the AMERBs have acquired for fishers, these kinds of systems need flexible regulations in order that fishers can adapt the system to local traditions, uses or needs and also to their learning and adapting capacities.
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| 3. |
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| 5. |
- Aeluri, Madhu, et al.
(författare)
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An Intramolecular Heck Approach To Obtain 17-Membered Macrocyclic Diversity and the Identification of an Antiangiogenesis Agent from a Zebrafish Assay
- 2013
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Ingår i: European Journal of Organic Chemistry. - : Wiley. - 1434-193X .- 1099-0690. ; :19, s. 3955-3958
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Tidskriftsartikel (refereegranskat)abstract
- We report a practical and modular approach to obtain two different types of 17-membered ring macrocyclic compounds through an intramolecular Heck reaction. These macrocyclic compounds are functionalized, that is, they contain two contiguous stereogenic hydroxy functional groups and an amino acid moiety in the macrocyclic ring skeleton. The macrocycles were then screened against a zebrafish assay to determine the antiangiogenesis activity of these small molecules. Macrocyclic compound 2.2a was identified as a potent inhibitor at 2.5 M, whereas its acyclic precursor and the other related macrocyclic compounds did not show any effect.
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| 6. |
- Agianian, Bogos, et al.
(författare)
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Preliminary characterization of hemolymph coagulation in Anopheles gambiae larvae
- 2007
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Ingår i: Developmental and Comparative Immunology. - : Elsevier BV. - 0145-305X .- 1879-0089. ; 31:9, s. 879-888
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Tidskriftsartikel (refereegranskat)abstract
- Hemolymph coagulation is a first response to injury, impeding infection, and ending bleeding. Little is known about its molecular basis in insects, but clotting factors have been identified in the fruit fly Drosophila melanogaster. Here, we have begun to study coagulation in the aquatic larvae of the malaria vector mosquito Anopheles gambiae using methods developed for Drosophila. A delicate clot was seen by light microscopy, and pullout and proteomic analysis identified phenoloxidase and apolipophorin-I as major candidate clotting factors. Electron microscopic analysis confirmed clot formation and revealed it contains fine molecular sheets, most likely a result of lipophorin assembly. Phenoloxidase appears to be more critical in clot formation in Anopheles than in Drosophila. The Anopheles larval clot thus differs in formation, structure, and composition from the clot in Drosophila, confirming the need to study coagulation in different insect species to learn more about its evolution and adaptation to different lifestyles.
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| 7. |
- Agvald-Öhman, C, et al.
(författare)
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Anaerobic bacteria commonly colonize the lower airways of intubated ICU patients
- 2003
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Ingår i: Clinical Microbiology and Infection. - : Elsevier BV. - 1198-743X .- 1469-0691. ; 9:5, s. 397-405
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Tidskriftsartikel (refereegranskat)abstract
- Objectives To investigate respiratory tract colonization by aerobic and anaerobic bacteria in mechanically ventilated patients. Methods Bacterial colonization of the stomach and the respiratory tract was qualitatively and quantitatively analyzed over time in 41 consecutive mechanically ventilated patients in a Swedish intensive care unit (ICU), with special emphasis on elucidation of the role of anaerobic bacteria in the lower respiratory tract. Samples were taken from the oropharynx, gastric juice, subglottic space and trachea within 24 h (median 14 h) of intubation, and then every third day until day 18 and every fifth day until day 33. Results The patients were often heavily colonized with microorganisms not considered to belong to a healthy normal oropharyngeal and gastric flora on admission to the ICU. A majority harbored enterococci, coagulase-negative staphylococci and Candida spp. in at least one site on day 1. Anaerobic bacteria, mainly peptostreptococci and Prevotella spp., were isolated from subglottic and/or tracheal secretions in 59% of the patients. Different routes of tracheal colonization for different groups of microorganisms were found. Primary or concomitant colonization of the oropharynx with staphylococci, enterococci, enterobacteria and Candida was often seen, while Pseudomonas spp., other non-fermenting Gram-negative rods and several anaerobic species often primarily colonized the trachea, indicating exogenous or direct gastrointestinal routes of colonization. Conclusions Mechanically ventilated patients were heavily colonized in their lower airways by potential pathogenic microorganisms, including a high load of anaerobic bacteria. Different routes of colonization were shown for different species.
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| 8. |
- Ahnström, G., et al.
(författare)
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The effect of dimethyl sulphoxide on the induction and repair of double-strand breaks in human cells after irradiation with γ-rays and accelerated ions : Rapid or slow repair may depend on accessibility of breaks in chromatin of different compactness
- 2000
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Ingår i: International Journal of Radiation Biology. - 0955-3002 .- 1362-3095. ; 76:4, s. 533-538
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The repair of double-strand breaks (dsb) in mammalian cells is characterized by a rapid phase with a half-life of less than half an hour and a slower phase that lasts for many hours. The proportion of slow repair increase with LET and it has been suggested that the slow repair component consists of more complex damage and is more deleterious to the cells. To see if removal of OH radicals could remove part of the damage in complex dsb and make them easier to repair, human cells were irradiated in the presence of dimethyl sulphoxide (DMSO). Methods: Induction and repair of dsb were studied by neutral elution in human VH10 cells exposed to γ-rays, helium ions (mean LET 40 keV/μm) and 80 and 125 keV/μm monoenergetic nitrogen ions in the presence and absence of 2 M DMSO. Results: Incubation of cells exposed to γ-rays, 40 keV/μm helium and 80 keV/μm N ions demonstrated that scavenging of OH radicals by DMSO removed most of the rapid repair component. The response to DMSO was less marked after 125 keV/μm nitrogen ions, where about half of the repair was resistant to DMSO. Conclusions: It is unlikely that the complexity of dsb is responsible for the slow repair because the removal of OH radicals did not make the breaks easier to repair. Instead, it is suggested that rapid and slow repair can be explained on the basis of how different parts of the chromatin are accessible to repair enzymes.
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| 9. |
- Al-Saqaf, Walid, 1973-, et al.
(författare)
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How Do Social Media Users Link Different Types of Extreme Events to Climate Change? : A Study of Twitter During 2008–2017
- 2019
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Ingår i: Journal of Extreme Events. - Singapore : World Scientific. - 2345-7376 .- 2382-6339. ; 06:02
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Tidskriftsartikel (refereegranskat)abstract
- This study examines how three types of extreme events (heat waves, droughts, floods) are mentioned together with climate change on social media. English-language Twitter use during 2008–2017 is analyzed, based on 1,127,996 tweets (including retweets). Frequencies and spikes of activity are compared and theoretically interpreted as reflecting complex relations between the extreme event factor (the occurrence of an extreme event); the media ecology factor (climate-change oriented statements/actions in the overall media landscape) and the digital action factor (activities on Twitter). Flooding was found to be by far the most tweeted of the three in connection to climate change, followed by droughts and heat waves. It also led when comparing spikes of activity. The dominance of floods is highly prevalent from 2014 onwards, triggered by flooding events (extreme event factor), the climate science controversy in US politics (media ecology factor) and the viral power of celebrities’ tweets (digital action factor).
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| 10. |
- Albernaz, Daniel L., et al.
(författare)
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Thermodynamics of a real fluid near the critical point in numerical simulations of isotropic turbulence
- 2016
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Ingår i: Physics of fluids. - : American Institute of Physics (AIP). - 1070-6631 .- 1089-7666. ; 28:12
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the behavior of a fluid near the critical point by using numerical simulations of weakly compressible three-dimensional isotropic turbulence. Much has been done for a turbulent flow with an ideal gas. The primary focus of this work is to analyze fluctuations of thermodynamic variables (pressure, density, and temperature) when a non-ideal Equation Of State (EOS) is considered. In order to do so, a hybrid lattice Boltzmann scheme is applied to solve the momentum and energy equations. Previously unreported phenomena are revealed as the temperature approaches the critical point. Fluctuations in pressure, density, and temperature increase, followed by changes in their respective probability density functions. Due to the non-linearity of the EOS, it is seen that variances of density and temperature and their respective covariance are equally important close to the critical point. Unlike the ideal EOS case, significant differences in the thermodynamic properties are also observed when the Reynolds number is increased. We also address issues related to the spectral behavior and scaling of density, pressure, temperature, and kinetic energy.
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