89 research outputs found
Infrared Multiple Photon Dissociation Action Spectroscopy and Theoretical Studies of Diethyl Phosphate Complexes: Effects of Protonation and Sodium Cationization on Structure
The gas-phase structures of deprotonated, protonated, and sodium-cationized complexes of diethyl phosphate (DEP) including [DEP − H]−, [DEP + H]+, [DEP + Na]+, and [DEP − H + 2Na]+ are examined via infrared multiple photon dissociation (IRMPD) action spectroscopy using tunable IR radiation generated by a free electron laser, a Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS) with an electrospray ionization (ESI) source, and theoretical electronic structure calculations. Measured IRMPD spectra are compared to linear IR spectra calculated at the B3LYP/6-31G(d,p) level of theory to identify the structures accessed in the experimental studies. For comparison, theoretical studies of neutral complexes are also performed. These experiments and calculations suggest that specific geometric changes occur upon the binding of protons and/or sodium cations, including changes correlating to nucleic acid backbone geometry, specifically P–O bond lengths and ∠OPO bond angles. Information from these observations may be used to gain insight into the structures of more complex systems, such as nucleotides and solvated nucleic acids
High-throughput profiling of caenorhabditis elegans starvation-responsive microRNAs
MicroRNAs (miRNAs) are non-coding RNAs of ~22 nucleotides in length that regulate gene expression by interfering with the stability and translation of mRNAs. Their expression is regulated during development, under a wide variety of stress conditions and in several pathological processes. In nature, animals often face feast or famine conditions. We observed that subjecting early L4 larvae from Caenorhabditis elegans to a 12-hr starvation period produced worms that are thinner and shorter than well-fed animals, with a decreased lipid accumulation, diminished progeny, reduced gonad size, and an increased lifespan. Our objective was to identify which of the 302 known miRNAs of C. elegans changed their expression under starvation conditions as compared to well-fed worms by means of deep sequencing in early L4 larvae. Our results indicate that 13 miRNAs (miR-34-3p, the family of miR-35-3p to miR-41-3p, miR-39-5p, miR-41-5p, miR-240-5p, miR-246-3p and miR-4813-5p) were upregulated, while 2 miRNAs (let-7-3p and miR-85-5p) were downregulated in 12-hr starved vs. well-fed early L4 larvae. Some of the predicted targets of the miRNAs that changed their expression in starvation conditions are involved in metabolic or developmental process. In particular, miRNAs of the miR-35 family were upregulated 6-20 fold upon starvation. Additionally, we showed that the expression of gld-1, important in oogenesis, a validated target of miR-35-3p, was downregulated when the expression of miR-35-3p was upregulated. The expression of another reported target, the cell cycle regulator lin-23, was unchanged during starvation. This study represents a starting point for a more comprehensive understanding of the role of miRNAs during starvation in C. elegans
Large-scale unit commitment under uncertainty: an updated literature survey
The Unit Commitment problem in energy management aims at finding the optimal production schedule of a set of generation units, while meeting various system-wide constraints. It has always been a large-scale, non-convex, difficult problem, especially in view of the fact that, due to operational requirements, it has to be solved in an unreasonably small time for its size. Recently, growing renewable energy shares have strongly increased the level of uncertainty in the system, making the (ideal) Unit Commitment model a large-scale, non-convex and uncertain (stochastic, robust, chance-constrained) program. We provide a survey of the literature on methods for the Uncertain Unit Commitment problem, in all its variants. We start with a review of the main contributions on solution methods for the deterministic versions of the problem, focussing on those based on mathematical programming techniques that are more relevant for the uncertain versions of the problem. We then present and categorize the approaches to the latter, while providing entry points to the relevant literature on optimization under uncertainty. This is an updated version of the paper "Large-scale Unit Commitment under uncertainty: a literature survey" that appeared in 4OR 13(2), 115--171 (2015); this version has over 170 more citations, most of which appeared in the last three years, proving how fast the literature on uncertain Unit Commitment evolves, and therefore the interest in this subject
Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine
[This corrects the article DOI: 10.1186/s13054-016-1208-6.]
Conservation of Mediterranean oak woodlands: understorey dynamics under different shrub management
The effect of experimental disturbances
on the dynamics of a shrub community was studied
on a ‘Montado’ ecosystem, in southern Portugal. The
evolution of the community physiognomy, composition
and diversity were monitored after shrub clearing
followed by biomass removal, deposition on soil
surface and incorporation with the soil, over a 9-year
period. Maximum shrub density was recorded in the
first year after the disturbances, excepting in mulched
plots which showed the greatest number of individuals
1 year later. The increment of shrub leaf biomass
was very fast in the first 3 years, whereas wood
production was slower but occurred along the whole
study period. At the end of the study, leaf and wood
biomass was still significantly lower than in the predisturbance
situation. The variation pattern of leaf
area index was similar to that of leaf biomass. The
evolution of total plant cover and diversity was
similar across treatments. The highest species richness
and diversity were recorded 2 years after
cutting, decreasing afterwards with the increasing
dominance of shrubs. Thus it seems likely that,
although a 9 year period is too short for these
communities to reach steady equilibrium, they are
very resistant and resilient to disturbances, as regeneration
was fast and vegetation dynamics was not
influenced by differences among treatments. We can
conclude that shrub clearing promotes biodiversity
and the time of permanence of shrub patches depends
on the particular goal we want to achieve
Conservation of Mediterranean oak woodlands: understorey dynamics under different shrub management
The effect of experimental disturbances
on the dynamics of a shrub community was studied
on a ‘Montado’ ecosystem, in southern Portugal. The
evolution of the community physiognomy, composition
and diversity were monitored after shrub clearing
followed by biomass removal, deposition on soil
surface and incorporation with the soil, over a 9-year
period. Maximum shrub density was recorded in the
first year after the disturbances, excepting in mulched
plots which showed the greatest number of individuals
1 year later. The increment of shrub leaf biomass
was very fast in the first 3 years, whereas wood
production was slower but occurred along the whole
study period. At the end of the study, leaf and wood
biomass was still significantly lower than in the predisturbance
situation. The variation pattern of leaf
area index was similar to that of leaf biomass. The
evolution of total plant cover and diversity was
similar across treatments. The highest species richness
and diversity were recorded 2 years after
cutting, decreasing afterwards with the increasing
dominance of shrubs. Thus it seems likely that,
although a 9 year period is too short for these
communities to reach steady equilibrium, they are
very resistant and resilient to disturbances, as regeneration
was fast and vegetation dynamics was not
influenced by differences among treatments. We can
conclude that shrub clearing promotes biodiversity
and the time of permanence of shrub patches depends
on the particular goal we want to achieve
Conservation of Mediterranean oak woodlands: understorey dynamics under different shrub management
Reduction in adverse effects of tracking devices on waterfowl requires better measuring and reporting
Jerky active matter: a phase field crystal model with translational and orientational memory
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