172 research outputs found
Quartic double solids with ordinary singularities
We study the mixed Hodge structure on the third homology group of a threefold
which is the double cover of projective three-space ramified over a quartic
surface with a double conic. We deal with the Torelli problem for such
threefolds.Comment: 14 pages, presented at the Conference Arnol'd 7
Oxalic acid hydrogenation to glycolic acid:heterogeneous catalysts screening
To meet our ambitions of a future circular economy and drastically reduce CO2 emissions, we need to make use of CO2 as a feedstock. Turning CO2 into monomers to produce sustainable plastics is an attractive option for this purpose. It can be achieved by electrochemical reduction of CO2 to formic acid derivatives, that can subsequently be converted into oxalic acid. Oxalic acid can be a monomer itself and it is a potential new platform chemical for material production, as useful monomers such as glycolic acid and ethylene glycol can be derived from it. Today the most common route from oxalic acid to glycolic acid requires multiple steps as it proceeds via oxalic acid di-esters as intermediates. In this work, we aim to avoid the extra reaction step of esterification. We explore the direct conversion of oxalic acid to glycolic acid in a two-step approach. In the first step, we define the ideal reaction conditions and test commercially available catalysts. We show that the reduction of oxalic acid can be performed at much lower temperatures and glycolic acid yields higher than those reported previously can be obtained. In the second step, we explore the design principles required for ideal catalysts which avoid the formation of acetic acid and ethylene glycol as side products. We show that ruthenium is the most active metal for the reaction and that carbon appears the most suitable support for these catalysts. By adding tin as a promotor, we could increase the selectivity and yield further whilst maintaining high activity of the resulting catalyst. This research lays the foundation for the efficient direct reduction of oxalic acid to glycolic acid and defines the design parameters for even better catalysts and the ideal process and conditions.</p
Aiming higher to bend the curve of biodiversity loss
The development of the post-2020 strategic plan for the Convention on Biological Diversity provides a vital window of opportunity to set out an ambitious plan of action to restore global biodiversity. The components of such a plan, including its goal, targets and some metrics, already exist and provide a roadmap to 2050
Основные положения формирования нового единого сельскохозяйственного налога
Обосновывается введение единого сельскохозяйственного налога как постоянной ставки от стоимости валового дохода предприятий.Обгрунтовується введене єдиного сільськогосподарського податку як
постійної ставки до вартості валового доходу підприємств.Introduction of the united agricultural tax is grounded as a permanent size to the
cost of gross profit of enterprises
Population change in breeding boreal waterbirds in a 25-year perspective : What characterises winners and losers?
Understanding drivers of variation and trends in biodiversity change is a general scientific challenge, but also crucial for conservation and management. Previous research shows that patterns of increase and decrease are not always consistent at different spatial scales, calling for approaches combining the latter. We here explore the idea that functional traits of species may help explaining divergent population trends. Complementing a previous community level study, we here analyse data about breeding waterbirds on 58 wetlands in boreal Fennoscandia, covering gradients in latitude as well as trophic status. We used linear mixed models to address how change in local abundance over 25 years in 25 waterbird species are associated with life history traits, diet, distribution, breeding phenology, and habitat affinity. Mean abundance increased in 10 species from 1990/1991 to 2016, whereas it decreased in 15 species. Local population increases were associated with species that are early breeders and have small clutches, an affinity for luxurious wetlands, an herbivorous diet, and a wide breeding range rather than a southern distribution. Local decreases, by contrast, were associated with species having large clutches and invertivorous diet, as well as being late breeders and less confined to luxurious wetlands. The three species occurring on the highest number of wetlands all decreased in mean abundance. The fact that early breeders have done better than late fits well with previous research about adaptability to climate change, that is, response to earlier springs. We found only limited support for the idea that life history traits are good predictors of wetland level population change. Instead, diet turned out to be a strong candidate for an important driver of population change, as supported by a general decrease of invertivores and a concomitant increase of large herbivores. In a wider perspective, future research needs to address whether population growth of large-bodied aquatic herbivores affects abundance of co-occurring invertivorous species, and if so, if this is due to habitat alteration, or to interference or exploitative competition.Peer reviewe
Early nasogastric tube feeding in optimising treatment for hyperemesis gravidarum: The MOTHER randomised controlled trial (Maternal and Offspring outcomes after Treatment of HyperEmesis by Refeeding)
Background: Hyperemesis gravidarum (HG), or intractable vomiting during pregnancy, is the single most frequent cause of hospital admission in early pregnancy. HG has a major impact on maternal quality of life and has repeatedly been associated with poor pregnancy outcome such as low birth weight. Currently, women with HG are admitted to hospital for intravenous fluid replacement, without receiving specific nutritional attention. Nasogastric tube feeding is sometimes used as last resort treatment. At present no randomised trials on dietary or rehydration interventions have been performed. Small observational studies indicate that enteral tube feeding may have the ability to effectively treat dehydration and malnutrition and alleviate nausea and vomiting symptoms. We aim to evaluate the effectiveness of early enteral tube feeding in addition to standard care on nausea and vomiting symptoms and pregnancy outcomes in HG patients. Methods/Design: The MOTHER trial is a multicentre open label randomised controlled trial ( www.studies-obsgyn.nl/mother ). Women ≥ 18 years hospitalised for HG between 5 + 0 and 19 + 6 weeks gestation are eligible for participation. After informed consent participants are randomly allocated to standard care with intravenous rehydration or early enteral tube feeding in addition to standard care. All women keep a weekly diary to record symptoms and dietary intake until 20 weeks gestation. The primary outcome will be neonatal birth weight. Secondary outcomes will be the 24-h Pregnancy Unique Quantification of Emesis and nausea score (PUQE-24), maternal weight gain, dietary intake, duration of hospital stay, number of readmissions, quality of life and side-effects. Also gestational age at birth, placental weight, umbilical cord plasma lipid concentration and neonatal morbidity will be evaluated. Analysis will be according to the intention to treat principle. Discussion: With this trial we aim to clarify whether early enteral tube feeding is more effective in treating HG than intravenous rehydration alone and improves pregnancy outcome. Trial registration: Trial registration number: NTR4197. Date of registration: October 2nd 2013
Work and Health, a Blind Spot in Curative Healthcare? A Pilot Study
Introduction Most workers with musculoskeletal disorders on sick leave often consult with regular health care before entering a specific work rehabilitation program. However, it remains unclear to what extent regular healthcare contributes to the timely return to work (RTW). Moreover, several studies have indicated that it might postpone RTW. There is a need to establish the influence of regular healthcare on RTW as outcome; “Does visiting a regular healthcare provider influence the duration of sickness absence and recurrent sick leave due to musculoskeletal disorders?”. Methods A cohort of workers on sick leave for 2–6 weeks due to a-specific musculoskeletal disorders was followed for 12 months. The main outcomes for the present analysis were: duration of sickness absence till 100% return to work and recurrent sick leave after initial RTW. Cox regression analyses were conducted with visiting a general health practitioner, physical therapist, or medical specialist during the sick leave period as independent variables. Each regression model was adjusted for variables known to influence health care utilization like age, sex, diagnostic group, pain intensity, functional disability, general health perception, severity of complaints, job control, and physical load at work. Results Patients visiting a medical specialist reported higher pain intensity and more functional limitations and also had a worse health perception at start of the sick leave period compared with those not visiting a specialist. Visiting a medical specialist delayed return to work significantly (HR = 2.10; 95%CI 1.43–3.07). After approximately 8 weeks on sick leave workers visiting a physical therapist returned to work faster than other workers. A recurrent episode of sick leave during the follow up quick was initiated by higher pain intensity and more functional limitations at the moment of fully return to work. Visiting a primary healthcare provider during the sickness absence period did not influence the occurrence of a new sick leave period. Conclusion Despite the adjustment for severity of the musculoskeletal disorder, visiting a medical specialist was associated with a delayed full return to work. More attention to the factor ‘labor’ in the regular healthcare is warranted, especially for those patients experiencing substantial functional limitations due to musculoskeletal disorders
Thyroid-stimulating hormone and free thyroxine fail to predict the severity and clinical course of hyperemesis gravidarum : A prospective cohort study
Funding information: This prospective cohort study was supported by a research grant from North West Hospital Group, Alkmaar, the Netherlands (Grant number: 2013T085) and by a research grant from the Amsterdam Reproduction and Development (AR&D) Research Institute, Amsterdam UMC, the Netherlands (Project number: 23346). ACKNOWLEDGMENTS We thank Dr. J.P. Bestwick (employed at Queen Mary University of London, London, UK) and Professor Dr. J.H. Lazarus (employed at Cardiff School of Medicine, Cardiff, UK) for providing TSH medians from their study in the UK. Dr. J.P. Bestwick and Professor Dr. Lazarus have nothing to disclose.Peer reviewedPublisher PD
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