scholarly journals Sediment phosphorus speciation and mobility under dynamic redox conditions

2017 ◽  
Author(s):  
Chris T. Parsons ◽  
Fereidoun Rezanezhad ◽  
David W. O'Connell ◽  
Philippe Van Cappellen
Keyword(s):  
Bottom Water ◽  
Sediment Resuspension ◽  
Total Duration ◽  
Redox Conditions ◽  
Phosphorus Speciation ◽  
Short Term ◽  
Nitrogen Gas ◽  
P Accumulation ◽  
Mn Oxides ◽  
Insight Into

Abstract. Anthropogenic nutrient enrichment has caused phosphorus (P) accumulation in many freshwater sediments, raising concerns that internal loading from legacy P may delay the recovery of aquatic ecosystems suffering from eutrophication. Benthic recycling of P strongly depends on the redox regime at the sediment-water interface (SWI) that, in many shallow environments, tends to be highly dynamic as a result of, among others, bioturbation by macrofauna, root activity, sediment resuspension and seasonal variations in bottom water oxygen (O2) concentrations. To gain insight into the mobility and biogeochemistry of P under fluctuating redox conditions, a suspension of sediment from a hyper-eutrophic freshwater marsh was exposed to alternating 7-day periods of purging with air and nitrogen gas (N2), for a total duration of 74 days. At the start of each anoxic period, algal necromass was added to simulate the deposition of fresh autochtonous organic matter. Phosphatase activities up to 2.4 mmol h−1 kg−1 indicated the potential for rapid mineralization of added organic-P (Po), in particular during the periods of aeration when the activity of phosphomonoesterases was up to 37 % higher than under N2 sparging. Aqueous phosphate concentrations remained low (~2.5 µM) under oxic conditions, due to sorption to Fe/Mn-oxides. During anoxic periods, once nitrate was depleted, the reductive dissolution of Fe/Mn-oxides released P. However, only 4.5 % of the released P accumulated in solution while the rest was redistributed among the particulate phases, including the humic fraction. Thus, under the relatively short-term redox fluctuations imposed in the experiments, P remobilization to the aqueous phase remained relatively limited and poly-phosphate did not accumulate. The results also emphasize the important control bottom water nitrate concentrations may exert on internal P loading in eutrophic environments.

scholarly journals Sediment phosphorus speciation and mobility under dynamic redox conditions

2017 ◽  
Vol 14 (14) ◽  
pp. 3585-3602 ◽  
Author(s):  
Chris T. Parsons ◽  
Fereidoun Rezanezhad ◽  
David W. O'Connell ◽  
Philippe Van Cappellen
Keyword(s):  
Aqueous Phase ◽  
Bottom Water ◽  
Solid Phase ◽  
Sediment Resuspension ◽  
Hydrolytic Enzyme ◽  
Total Duration ◽  
Redox Conditions ◽  
Phosphorus Speciation ◽  
Bioreactor System ◽  
Phase Chemistry

Abstract. Anthropogenic nutrient enrichment has caused phosphorus (P) accumulation in many freshwater sediments, raising concerns that internal loading from legacy P may delay the recovery of aquatic ecosystems suffering from eutrophication. Benthic recycling of P strongly depends on the redox regime within surficial sediment. In many shallow environments, redox conditions tend to be highly dynamic as a result of, among others, bioturbation by macrofauna, root activity, sediment resuspension and seasonal variations in bottom-water oxygen (O2) concentrations. To gain insight into the mobility and biogeochemistry of P under fluctuating redox conditions, a suspension of sediment from a hypereutrophic freshwater marsh was exposed to alternating 7-day periods of purging with air and nitrogen gas (N2), for a total duration of 74 days, in a bioreactor system. We present comprehensive data time series of bulk aqueous- and solid-phase chemistry, solid-phase phosphorus speciation and hydrolytic enzyme activities demonstrating the mass balanced redistribution of P in sediment during redox cycling. Aqueous phosphate concentrations remained low ( ∼  2.5 µM) under oxic conditions due to sorption to iron(III) oxyhydroxides. During anoxic periods, once nitrate was depleted, the reductive dissolution of iron(III) oxyhydroxides released P. However, only 4.5 % of the released P accumulated in solution while the rest was redistributed between the MgCl2 and NaHCO3 extractable fractions of the solid phase. Thus, under the short redox fluctuations imposed in the experiments, P remobilization to the aqueous phase remained relatively limited. Orthophosphate predominated at all times during the experiment in both the solid and aqueous phase. Combined P monoesters and diesters accounted for between 9 and 16 % of sediment particulate P. Phosphatase activities up to 2.4 mmol h−1 kg−1 indicated the potential for rapid mineralization of organic P (Po), in particular during periods of aeration when the activity of phosphomonoesterases was 37 % higher than under N2 sparging. The results emphasize that the magnitude and timing of internal P loading during periods of anoxia are dependent on both P redistribution within sediments and bottom-water nitrate concentrations.

A Bird in the Hand Isn’t Good for Long

2018 ◽  
Vol 65 (1) ◽  
pp. 23-31 ◽  
Author(s):  
Stefan Scherbaum ◽  
Simon Frisch ◽  
Maja Dshemuchadse
Keyword(s):  
Decision Making ◽  
Cognitive Control ◽  
The Other ◽  
Decision Task ◽  
Short Term ◽  
Additional Time ◽  
Control Processes ◽  
Folk Wisdom ◽  
Study Participants ◽  
Insight Into

Abstract. Folk wisdom tells us that additional time to make a decision helps us to refrain from the first impulse to take the bird in the hand. However, the question why the time to decide plays an important role is still unanswered. Here we distinguish two explanations, one based on a bias in value accumulation that has to be overcome with time, the other based on cognitive control processes that need time to set in. In an intertemporal decision task, we use mouse tracking to study participants’ responses to options’ values and delays which were presented sequentially. We find that the information about options’ delays does indeed lead to an immediate bias that is controlled afterwards, matching the prediction of control processes needed to counter initial impulses. Hence, by using a dynamic measure, we provide insight into the processes underlying short-term oriented choices in intertemporal decision making.

scholarly journals Using syndromic measures of mortality to capture the dynamics of COVID-19 in Java, Indonesia, in the context of vaccination rollout

BMC Medicine ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Bimandra A. Djaafara ◽  
Charles Whittaker ◽  
Oliver J. Watson ◽  
Robert Verity ◽  
Nicholas F. Brazeau ◽  
...  
Keyword(s):  
Rural Areas ◽  
Vaccination Campaign ◽  
Control Measures ◽  
Additional Insight ◽  
Short Term ◽  
If Current ◽  
Vaccine Impact ◽  
Potential Impact ◽  
The Impact ◽  
Insight Into

Abstract Background As in many countries, quantifying COVID-19 spread in Indonesia remains challenging due to testing limitations. In Java, non-pharmaceutical interventions (NPIs) were implemented throughout 2020. However, as a vaccination campaign launches, cases and deaths are rising across the island. Methods We used modelling to explore the extent to which data on burials in Jakarta using strict COVID-19 protocols (C19P) provide additional insight into the transmissibility of the disease, epidemic trajectory, and the impact of NPIs. We assess how implementation of NPIs in early 2021 will shape the epidemic during the period of likely vaccine rollout. Results C19P burial data in Jakarta suggest a death toll approximately 3.3 times higher than reported. Transmission estimates using these data suggest earlier, larger, and more sustained impact of NPIs. Measures to reduce sub-national spread, particularly during Ramadan, substantially mitigated spread to more vulnerable rural areas. Given current trajectory, daily cases and deaths are likely to increase in most regions as the vaccine is rolled out. Transmission may peak in early 2021 in Jakarta if current levels of control are maintained. However, relaxation of control measures is likely to lead to a subsequent resurgence in the absence of an effective vaccination campaign. Conclusions Syndromic measures of mortality provide a more complete picture of COVID-19 severity upon which to base decision-making. The high potential impact of the vaccine in Java is attributable to reductions in transmission to date and dependent on these being maintained. Increases in control in the relatively short-term will likely yield large, synergistic increases in vaccine impact.

Specialist infantry and defence engagement

2020 ◽  
pp. bmjmilitary-2020-001455 ◽  
Author(s):  
Jonathan Blair Thomas Herron ◽  
K M Heil ◽  
D Reid
Keyword(s):  
Armed Forces ◽  
Short Term ◽  
The Future ◽  
Uk Government ◽  
The Uk ◽  
Insight Into

In 2015, the UK government published the National Strategic Defence and Security Review (SDSR) 2015, which laid out their vision for the future roles and structure of the UK Armed Forces. SDSR 2015 envisaged making broader use of the Armed Forces to support missions other than warfighting. One element of this would be to increase the scale and scope of defence engagement (DE) activities that the UK conducts overseas. DE activities traditionally involve the use of personnel and assets to help prevent conflict, build stability and gain influence with partner nations as part of a short-term training teams. This paper aimed to give an overview of the Specialist Infantry Group and its role in UK DE. It will explore the reasons why the SDSR 2015 recommended their formation as well as an insight into future tasks.

Chrysophycean Microfossils Provide New Insight into the Recent History of a Naturally Acidic Lake (Cone Pond, New Hampshire)

1987 ◽  
Vol 44 (9) ◽  
pp. 1584-1588 ◽  
Author(s):  
Katherine N. Gibson ◽  
John P. Smol ◽  
Jesse Ford
Keyword(s):  
New Hampshire ◽  
Early Spring ◽  
Recent Change ◽  
Fish Populations ◽  
Short Term ◽  
Acidic Lake ◽  
Lake Water Chemistry ◽  
History Of ◽  
Early Snowmelt ◽  
Insight Into

Cone Pond, New Hampshire, is an acidic (pH = 4.5) clearwater lake that is currently fishless. Historical records indicate declining fish populations between 1951 and 1966, but paleolimnological work using diatoms failed to find evidence for further recent acidification of this naturally acid site. We initiated new paleolimnological studies using mallomonadacean chrysophytes to further our understanding of Cone Pond's recent past. Our stratigraphic analyses indicate recent striking changes in the chrysophyte flora of this lake, with Mallomonas hindonii, a species only common in recently acidified lakes, replacing M. crassisquama, a cosmopolitan species that dominated the flora over the preceding 8000 yr; this recent change parallels the declines in fish populations. Because chrysophytes often bloom in early spring and are known, in other lakes, to experience changes in community composition before those expressed by the diatom community, a possibility is that chrysophytes track transient excursions of lake water chemistry associated with early snowmelt conditions. In this scenario, chrysophytes would respond to a constellation of specific short-term chemical changes including, but not restricted to, pH. Such pH associated changes could include changes in concentrations, speciation, or complexation of metals mobilized from the catchment or sediments, all of which are known to affect both chrysophytes and fish.

Athletes Play Through Pain—What Does That Mean for Rehabilitation Specialists?

2020 ◽  
Vol 29 (5) ◽  
pp. 640-649 ◽  
Author(s):  
Amy Barrette ◽  
Katherine Harman
Keyword(s):  
Well Being ◽  
Short Term ◽  
Semistructured Interviews ◽  
Sport Organization ◽  
The University ◽  
E Mail ◽  
Competitive Nature ◽  
And Training ◽  
Insight Into

Context: Pain in sport has been normalized to the point where athletes are expected to ignore pain and remain in the game despite the possible detrimental consequences associated with playing through pain. While rehabilitation specialists may not have an influence on an athlete’s competitive nature or the culture of risk they operate in, understanding the consequences of those factors on an athlete’s physical well-being is definitely in their area of responsibility. Objective: To explore the factors associated with the experiences of subelite athletes who play through pain in gymnastics, rowing, and speed skating. Design: The authors conducted semistructured interviews with subelite athletes, coaches, and rehabilitation specialists. They recruited coach participants through their provincial sport organization. Athletes of the recruited coaches who were recovering from a musculoskeletal injury and training for a major competition were then recruited. They also recruited rehabilitation specialists who were known to treat subelite athletes independently by e-mail. Setting: An observation session was conducted at the athlete’s training facility. Interviews were then conducted either in a room at the university or at a preferred sound-attenuated location suggested by the participant. Participants: The authors studied 5 coaches, 4 subelite athletes, and 3 rehabilitation specialists. Interventions: The authors photographed athletes during a practice shortly before an important competition, and we interviewed all the participants after that competition. Our photographs were used during the interview to stimulate discussion. Results: The participant interviews revealed 3 main themes related to playing through pain. They are: Listening to your body, Decision making, and Who decides. Conclusion: When subelite athletes, striving to be the best in their sport continue to train with the pain of an injury, performance is affected in the short-term and long-term consequences are also possible. Our study provides some insight into the contrasting forces that athletes balance as they decide to continue or to stop.

scholarly journals Characterization of Terrihabitans soli gen. nov., sp. nov., a Novel 0.2 μm-Filterable Soil Bacterium Belonging to a Widely Distributed Lineage of Hyphomicrobiales (Rhizobiales)

Diversity ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 422
Author(s):  
Ryosuke Nakai ◽  
Takeshi Naganuma ◽  
Nozomi Tazato ◽  
Tadao Kunihiro ◽  
Sho Morohoshi ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Cellular Fatty Acid ◽  
The Novel ◽  
Nitrogen Gas ◽  
Nitrogen Fixers ◽  
Novel Genus And Species ◽  
Ubiquinone 10 ◽  
Type Strains ◽  
Insight Into

We previously showed that novel filterable bacteria remain in “sterile” (<0.2 μm filtered) terrestrial environmental samples from Japan, China, and Arctic Norway. Here, we characterized the novel filterable strain IZ6T, a representative strain of a widely distributed lineage. Phylogenetic analysis showed that this strain was affiliated with the Rhizobiales (now proposed as Hyphomicrobiales) of Alphaproteobacteria, but distinct from any other type strains. Strain IZ6T shared the following chemotaxonomic features with the closest (but distantly) related type strain, Flaviflagellibacter deserti SYSU D60017T: ubiquinone-10 as the major quinone; phosphatidylethanolamine, phosphatidylcholine, and phosphatidylglycerol as major polar lipids; and slightly high G+C content of 62.2 mol%. However, the cellular fatty acid composition differed between them, and the unsaturated fatty acid (C18:1ω7c/C18:1ω6c) was predominantly found in our strain. Moreover, unlike methyrotrophs and nitrogen-fixers of the neighboring genera of Hyphomicrobiales (Rhizobiales), strain IZ6T cannot utilize a one-carbon compound (e.g., methanol) and fix atmospheric nitrogen gas. These findings were consistent with the genome-inferred physiological potential. Based on the phylogenetic, physiological, and chemotaxonomic traits, we propose that strain IZ6T represents a novel genus and species with the name Terrihabitans soli gen. nov., sp. nov. (=NBRC 106741T = NCIMB 15058T). The findings will provide deeper insight into the eco-physiology of filterable microorganisms.

scholarly journals Az etopozid szervezeten belüli eloszlásában és metabolizmusában szerepet játszó epigenetikai hatások

2018 ◽  
Vol 159 (32) ◽  
pp. 1295-1302
Author(s):  
Erika Rozália Kovács ◽  
Sára Tóth ◽  
Dániel János Erdélyi
Keyword(s):  
Topoisomerase Ii ◽  
Therapeutic Index ◽  
Antitumor Agent ◽  
Hematologic Malignancies ◽  
Short Term ◽  
Drug Dosing ◽  
And Personalized Medicine ◽  
Insight Into ◽  
Pharmacogenomic Studies

Abstract: Etoposide is a topoisomerase II inhibitor antitumor agent which is widely used in the treatment of several hematologic malignancies and solid tumors. The therapeutic index of etoposide is quite high, thus its application causes several short-term and long-term side effects which can decrease the chance to cure patients. Drug dosing is based on body surface area calculation; recommendations for individual dosing do not exist yet. The biotransformation and transportation of etoposide are carried out by enzymes and transporters as reported in pharmacogenomic studies published in this area. Nowadays pharmacoepigenetics research has come to the fore. The authors wish to give an insight into the research of the epigenetical changes of the etoposide pathways, especially focusing on published findings on enzymes and transporters with pharmacokinetic relevance. In the future, epigenetical changes of the etoposide pathway might have a great role in diagnostics, prognostics and personalized medicine. Orv Hetil. 2018; 159(32): 1295–1302.

Intra-arterial chemotherapy for retinoblastoma: an updated systematic review and meta-analysis

2019 ◽  
Vol 11 (12) ◽  
pp. 1266-1272 ◽  
Author(s):  
Krishnan Ravindran ◽  
Lauren A Dalvin ◽  
Jose S Pulido ◽  
Waleed Brinjikji
Keyword(s):  
Metastatic Disease ◽  
Meta Analysis ◽  
Inclusion Criteria ◽  
First Line ◽  
Short Term ◽  
Systemic Complications ◽  
Substantial Heterogeneity ◽  
Insight Into

Background and purposeIntra-arterial chemotherapy for retinoblastoma has been adopted as a first-line treatment option by numerous tertiary centers. The effect of intra-arterial chemotherapy on future rates of metastatic disease as well as on globe salvage in advanced eyes remains relatively unknown.MethodsA search of PubMED, MEDLINE, EMBASE, and Web of Science electronic databases was conducted from inception until January 2019 for studies with a minimum of 10 patients reporting outcomes and complications following intra-arterial chemotherapy for retinoblastoma.ResultsA total of 20 studies met the inclusion criteria for analysis, comprising 873 patients and 1467 eyes. Only one study was comparative; there was substantial heterogeneity in reported outcomes and several overlapping patient cohorts that were published. Across all studies, 174 of 1467 eyes were enucleated (11.8%). Metastatic disease occurred in 8 of 513 patients (1.6%). Globe salvage was achieved in 318 of 906 (35.6%) cases of advanced retinoblastoma. The most common ocular complication was retinal detachment, occurring in 23% of eyes, and the most common systemic complications were transient fever and nausea/vomiting.ConclusionsThere is a paucity of higher-level evidence with adequate follow-up surrounding the long-term safety of intra-arterial chemotherapy and effect on metastasis in retinoblastoma. Studies to date have been limited by short-term follow-up. Longitudinal prospective studies could provide greater insight into the ability of intra-arterial chemotherapy to reduce the risk of retinoblastoma metastasis.

New insight into the behaviour modifying activity of two natural sesquiterpenoids farnesol and nerolidol towards Myzus persicae (Sulzer) (Homoptera: Aphididae)

2019 ◽  
Vol 110 (2) ◽  
pp. 249-258 ◽  
Author(s):  
Anna Wróblewska-Kurdyk ◽  
Katarzyna Dancewicz ◽  
Anna Gliszczyńska ◽  
Beata Gabryś
Keyword(s):  
Myzus Persicae ◽  
Total Duration ◽  
Host Plant Selection ◽  
Electrical Penetration Graph ◽  
Potato Aphid ◽  
Epg Technique ◽  
The Mean ◽  
Freely Moving ◽  
Peach Potato Aphid ◽  
Insight Into

AbstractThe effect of structurally related sesquiterpenoids (E,E)-farnesol and cis-nerolidol on the host-plant selection behaviour of the peach potato aphid Myzus persicae (Sulz.) was evaluated using electrical penetration graph (EPG) technique. No repellent effects of (E,E)-farnesol and (Z)-nerolidol to M. persicae were found but aphid probing activities on (E,E)-farnesol- and cis-nerolidol-treated plants were restrained. During non-phloem phases of probing, neither (E,E)-farnesol nor (Z)-nerolidol affected the cell puncture activity. On (E,E)-farnesol-treated plants, the total duration of phloem phase, the mean duration of individual sustained ingestion periods were significantly lower, and the proportion of phloem salivation was higher than on control plants. On (Z)-nerolidol-treated plants, the occurrence of the first phloem phase was delayed, and the frequency of the phloem phase was lower than on control plants. The freely moving aphids were reluctant to remain on (E,E)-farnesol- and (Z)-nerolidol-treated leaves for at least 24 h after exposure. (E,E)-Farnesol and (Z)-nerolidol show complementary deterrent properties, (E,E)-farnesol showing ingestive and post-ingestive activities and nerolidol showing pre-ingestive, ingestive, and post-ingestive deterrent activities.

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