1,915 research outputs found
Assessment of <i>Miscanthus</i> × <i>giganteus</i> derived biochar as copper and zinc adsorbent:study of the effect of pyrolysis temperature, pH and hydrogen peroxide modification
In this work, experimental and modelling investigations were conducted on biochars pyrolyzed at 350 °C and 600 °C, to determine the effect of pyrolysis temperature, hydrogen peroxide activation and pH on copper and zinc removal, in comparison with commercially available activated carbons. Characterization of biochars was performed by BET surface area, elemental analysis and FTIR spectroscopy. Experiments results demonstrated that biochar pyrolyzed at 600 °C adsorbed both copper and zinc more efficiently than biochar pyrolyzed at 350 °C. Chemical activation by H2O2 increased the removal capacity of biochar pyrolyzed at 350 °C. All investigated biochars showed a stronger affinity for copper retention, with a maximum adsorption capacity of 15.7 mg/g while zinc was 10.4 mg/g. The best adsorption performances were obtained at pH 5 and 6. Langmuir adsorption isotherm described copper adsorption process satisfactorily, while zinc adsorption was better described by Freundlich isotherm
Motion of magnetotactic bacteria swarms in an external field
Magnetotactic bacteria moving on circular orbits form hydrodynamically bound
states. When close to a surface and with the tilting of the field in a
direction close to the perpendicular to this surface these swarms move
perpendicularly to the tilting angle. We describe quantitatively this motion by
a continuum model with couple stress arising from the torques produced by the
rotary motors of the amphitrichous magnetotactic bacteria. The model not only
correctly describes the change of direction of swarm motion while inverting the
tangential field but also predicts reasonable value of the torque produced by
the rotary motors
A longitudinal study on diarrhoea and vomiting in young dogs of four large breeds
<p>Abstract</p> <p>Background</p> <p>Prospective studies to document the occurrence of canine diarrhoea and vomiting are relatively scarce in dogs, and the majority of published studies are based on information from clinical records. This study investigates the incidence risk of diarrhoea and vomiting as well as potential risk factors.</p> <p>Methods</p> <p>A cohort study of 585 privately owned dogs of four breeds: Newfoundland, Labrador retriever, Leonberger, and Irish wolfhound. The owners maintained a continuous log regarding housing, exercise, nutrition, and health of their dogs. Episodes of diarrhoea and vomiting were recorded in a consecutive manner in a booklet. The owners completed the questionnaires and reported information at three, four, six, 12, 18, and 24/25 months of age, called observational ages.</p> <p>Associations with potential risk factors for diarrhoea and vomiting were investigated in separate generalized estimating equation analyses.</p> <p>Results</p> <p>The incidence of both diarrhoea and vomiting was influenced by breed. Both diarrhoea and vomiting were relatively common in young dogs, occurring most frequently during the first months of life. After three months of age, the odds of diarrhoea were significantly lower when compared to the observational period seven weeks to three months (OR ranging from 0.31 to 0.70 depending on the period). More males than females suffered from diarrhoea (OR = 1.42). The occurrence of diarrhoea was more common in dogs that also experienced episode(s) of vomiting during the study period (OR = 5.43) and <it>vice versa </it>(OR = 5.50). In the majority of dogs episodes of diarrhoea and vomiting did not occur at the same time. Dogs in urban areas had higher odds (OR = 1.88) of getting diarrhoea compared to dogs living in rural areas. The occurrence of both diarrhoea and vomiting demonstrated a seasonal variation with higher incidence during the summer months.</p> <p>Conclusion</p> <p>Both diarrhoea and vomiting occurred most frequently during the first months of life. The incidence of diarrhoea and vomiting was significantly different between breeds. Diarrhoea occurred more frequently in males and in dogs living in urban areas. Also, a positive association between the occurrence of diarrhoea and vomiting in the same dog was found.</p
Arctic Fox (Alopex Lagopus) Dens in the Disko Bay Area, West Greenland
Seventeen arctic fox (Alopex lagopus) dens in the Disko Bay area, West Greenland are described regarding location, type, size and vegetation cover. The dens were found in ridges, screes and level ground, mainly of dwarf-scrub heath. The mean number of entrances was 17.8±18.4 SD (range 1-63), with more than half of the dens having fewer than 10 entrances. For dens in slopes, there was a prevalence for south-facing slopes, but for dens with an open exposure, entrances were most frequently oriented towards the north and east. The dens were not found to be lush green, as reported from several other areas. A visual difference between the den vegetation and the surrounding vegetation could only be recognized at a few den sites. A vegetation analysis revealed a significant difference between the den and the surrounding area in the occurrence of eight plant species. Among the species occurring more frequently on the den than in the adjacent area, Stellaria longipes was the most conspicuous because of its white flowers. This species is therefore suggested as a guide species in the search for new dens in the Disko Bay area. Dens with recent fox activity were larger and more conspicuous than dens without sign of recent activity.Key words: Arctic fox, Alopex lagopus, den site, den vegetation, Disko Bay, West GreenlandOn donne une description des terriers de 17 renards arctiques (Alopex lagopus) dans la région de la baie de Disko, à l'ouest du Groenland, selon l'emplacement, le type, la dimension et le couvert végétal. Ces terriers avaient été creusés dans des crêtes, des éboulis et en terrain plat, surtout dans des zones où la végétation se composait d'arbustes nains. Le nombre d'entrées était de 17,8, avec un écart-type de 18,4 (gamme de 1 à 63), plus de la moitié des terriers ayant moins de 10 entrées. Les terriers creusés dans les talus étaient plutôt exposés au sud, mais ceux qui étaient ouverts avaient leurs entrées orientées le plus fréquemment vers le nord et vers l'est. On n'a pas trouvé de végétation très dense autour du terrier, comme cela avait été rapporté pour plusieurs autres endroits. On n'a pu faire de différence visuelle entre la végétation du terrier et la végétation à l'entour que sur quelques sites. Une analyse de la végétation a révélé une différence significative entre le terrier même et la zone à l'entour dans la présence de huit espèces de plantes. Parmi les espèces apparaissant plus fréquemment sur le site du terrier que dans la zone à l'entour, Stellaria longipes était la plus visible en raison de ses fleurs blanches. C'est pourquoi on suggère d'utiliser cette espèce comme un guide dans la recherche de nouveaux terriers creusés dans la région de la baie de Disko. Les terriers qui portaient des traces de la présence récente des renards étaient plus grands et plus visibles que les terriers qui ne montraient pas de traces de présence récente.Mots clés: renard arctique, Alopex lagopus, site du terrier, végétation de terrier, baie de Disko, Groenland occidenta
Urea production and turnover following the addition of AMP, CMP, RNA and a protein mixture to a marine sediment
The potential of adenosine 5′-monophosphate (AMP), cytidine 5′-monophosphate (CMP), 16S ribosomal RNA, and a protein (bovine serum albumin) to serve as substrates for bacterial urea production was evaluated in a defaunated, anoxic marine sediment. AMP, CMP and RNA stimulated urea production and urea turnover, but CMP to a lesser degree than AMP and RNA. The increase in urea production and turnover rates took place immediately after AMP, CMP, and RNA were added to the sediment. The rapid response in urea production and turnover rates suggests that the necessary uptake mechanisms and enzymes to utilize the substrates were present constitutively. Addition of the protein mixture did not result in any measurable changes in the urea pool size, urea turnover rate, or urea production rate during the 165 h of incubation. However, an increased and continuous net NH4+ production in the protein-amended sediment relative to the control sediment indicated that the added protein mixture was accessible for bacterial degradation. The results showed that purines and pyrimidines were substrates for the bacterial urea production in the marine sediment, whereas protein was not important for urea production
Extreme reproduction and survival of a true cliffhanger : the endangered plant Borderea chouardii (Dioscoreaceae)
Cliff sides are extreme habitats, often sheltering a rich and unique flora. One example is the dioecious herb Borderea chouardii (Dioscoreaceae), which is a Tertiary, tropical relict, occurring only on two adjacent vertical cliffs in the world. We studied its reproductive biology, which in some aspects is extreme, especially the unusual double mutualistic role of ants as both pollinators and dispersers. We made a 2-year pollination census and four years of seed-dispersal experiments, recording flower visitors and dispersal rates. Fruit and seed set, self-sowing of seeds, seedling recruitment, and fate of seedlings from seeds sowed by different agents were scored over a period of 17 years. The ants Lasius grandis and L. cinereus were the main pollinators, whereas another ant Pheidole pallidula dispersed seeds. Thus ants functioned as double mutualists. Two thirds of all new seedlings came from self-sown seeds, and 1/3 was dispersed by ants, which gathered the seeds with their oil-rich elaiosome. Gravity played a minor role to dispersal. Both ant dispersal and self-sowing resulted in the same survival rate of seedlings. A double mutualism is a risky reproductive strategy, but B. chouardii buffers that by an unusual long-term demographic stability (some individuals exceed 300 years in lifespan) and its presence in a climatically very stable habitat, inaccessible to large herbivores. Such a combination of traits and habitat properties may explain the persistence of this relict species
Development of the CNPP Prices Database
Data are available at: http://www.cnpp.usda.gov/USDAFoodPlansCostofFood.htmfood prices, USDA Food Plans, NHANES, CNPP Prices Database, Consumer/Household Economics, Demand and Price Analysis, Food Consumption/Nutrition/Food Safety,
Starting parenting in isolation a qualitative user-initiated study of parents’ experiences with hospitalization in Neonatal Intensive Care units during the COVID-19 pandemic
Background Worldwide, strict infection control measures including visitation regulations were implemented due to the COVID-19 pandemic at Neonatal Intensive Care Units (NICUs). These regulations gave restricted access for parents to their hospitalized infants. The consequence was limited ability to involve in the care of their infants. At Oslo University Hospital entry to NICU was denied to all except healthy mothers in March 2020. The absolute access ban for fathers lasted for 10 weeks. The aim of this study was to explore parental experiences with an infant hospitalized in the NICU during this absolute visitation ban period. Methods We invited post discharge all parents of surviving infants that had been hospitalized for at least 14 days to participate. They were interviewed during autumn 2020 using an explorative semi-structured interview approach. Data were analyzed via inductive thematic analysis. Results Nine mothers and four fathers participated. The COVID-19 regulations strongly impacted the parent’s experiences of their stay. The fathers’ limited access felt life-impacting. Parents struggled to become a family and raised their voices to be heard. Not being able to experience parenthood together led to emotional loneliness. The fathers struggled to learn how to care for their infant. The regulations might lead to a postponed attachment. On the other hand, of positive aspect the parents got some quietness. Being hospitalized during this first wave was experienced as exceptional and made parents seeking alliances by other parents. Social media was used to keep in contact with the outside world. Conclusions The regulations had strong negative impact on parental experiences during the NICU hospitalization. The restriction to fathers’ access to the NICU acted as a significant obstacle to early infant-father bonding and led to loneliness and isolation by the mothers. Thus, these COVID-19 measures might have had adverse consequences for families.publishedVersio
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