139 research outputs found
Possible Signatures of a Cold-Flow Disk from MUSE using a z=1 galaxy--quasar pair towards SDSSJ1422-0001
We use a background quasar to detect the presence of circum-galactic gas
around a low-mass star forming galaxy. Data from the new Multi Unit
Spectroscopic Explorer (MUSE) on the VLT show that the host galaxy has a
dust-corrected star-formation rate (SFR) of 4.70.2 Msun/yr, with no
companion down to 0.22 Msun/yr (5 ) within 240 kpc (30"). Using a
high-resolution spectrum (UVES) of the background quasar, which is fortuitously
aligned with the galaxy major axis (with an azimuth angle of only
), we find, in the gas kinematics traced by low-ionization lines,
distinct signatures consistent with those expected for a "cold flow disk"
extending at least 12 kpc (). We estimate the mass accretion
rate to be at least two to three times larger than the SFR,
using the geometric constraints from the IFU data and the HI column density of
obtained from a {\it HST}/COS NUV spectrum. From
a detailed analysis of the low-ionization lines (e.g. ZnII, CrII, TiII, MnII,
SiII), the accreting material appears to be enriched to about 0.4
(albeit with large uncertainties: ), which is
comparable to the galaxy metallicity (), implying a
large recycling fraction from past outflows. Blue-shifted MgII and FeII
absorptions in the galaxy spectrum from the MUSE data reveal the presence of an
outflow. The MgII and FeII doublet ratios indicate emission infilling due to
scattering processes, but the MUSE data do not show any signs of fluorescent
FeII* emission.Comment: 17 pages, 11 figures, in press (ApJ), minor edits after the proofs.
Data available at http://muse-vlt.eu/science/j1422
Incorporating shape constraints in generalized additive modelling of the height-diameter relationship for Norway spruce
Methane exchange in a boreal forest estimated by gradient method
Forests are generally considered to be net sinks of atmospheric methane (CH4) because of oxidation by methanotrophic bacteria in well-aerated forests soils. However, emissions from wet forest soils, and sometimes canopy fluxes, are often neglected when quantifying the CH4 budget of a forest. We used a modified Bowen ratio method and combined eddy covariance and gradient methods to estimate net CH4 exchange at a boreal forest site in central Sweden. Results indicate that the site is a net source of CH4. This is in contrast to soil, branch and leaf chamber measurements of uptake of CH4. Wetter soils within the footprint of the canopy are thought to be responsible for the discrepancy. We found no evidence for canopy emissions per se. However, the diel pattern of the CH4 exchange with minimum emissions at daytime correlated well with gross primary production, which supports an uptake in the canopy. More distant source areas could also contribute to the diel pattern; their contribution might be greater at night during stable boundary layer conditions
Biochar research activities and their relation to development and environmental quality. A meta-analysis
Second order optimality conditions and their role in PDE control
If f : Rn R is twice continuously differentiable, fâ(u) = 0 and fââ(u) is positive definite, then u is a local minimizer of f. This paper surveys the extension of this well known second order suffcient optimality condition to the case f : U R, where U is an infinite-dimensional linear normed space. The reader will be guided from the case of finite-dimensions via a brief discussion of the calculus of variations and the optimal control of ordinary differential equations to the control of nonlinear partial differential equations, where U is a function space. In particular, the following questions will be addressed: Is the extension to infinite dimensions straightforward or will unexpected difficulties occur? How second order sufficient optimality conditions must be modified, if simple inequality constraints are imposed on u? Why do we need second order conditions and how can they be applied? If they are important, are we able to check if they are fulfilled order sufficient optimality condition to the case f : U R, where U is an infinite-dimensional linear normed space. The reader will be guided from the case of finite-dimensions via a brief discussion of the calculus of variations and the optimal control of ordinary differential equations to the control of nonlinear partial differential equations, where U is a function space. In particular, the following questions will be addressed: Is the extension to infinite dimensions straightforward or will unexpected difficulties occur? How second order sufficient optimality conditions must be modified, if simple inequality constraints are imposed on u? Why do we need second order conditions and how can they be applied? If they are important, are we able to check if they are fulfilled?
It turns out that infinite dimensions cause new difficulties that do not occur in finite dimensions. We will be faced with the surprising fact that the space, where fââ(u) exists can be useless to ensure positive definiteness of the quadratic form v fââ(u)v2. In this context, the famous two-norm discrepancy, its consequences, and techniques for overcoming this difficulty are explained. To keep the presentation simple, the theory is developed for problems in function spaces with simple box constraints of the form a = u = Ă. The theory of second order conditions in the control of partial differential equations is presented exemplarily for the nonlinear heat equation. Different types of critical cones are introduced, where the positivity of fââ(u) must be required. Their form depends on whether a so-called Tikhonov regularization term is part of the functional f or not. In this context, the paper contains also new results that lead to quadratic growth conditions in the strong sense.
As a first application of second-order sufficient conditions, the stability of optimal solutions with respect to perturbations of the data of the control problem is discussed. Second, their use in analyzing the discretization of control problems by finite elements is studied. A survey on further related topics, open questions, and relevant literature concludes the paper.The first author was partially supported by the Spanish Ministerio de EconomĂa y Competitividad under project MTM2011-22711, the second author by DFG in the framework of the Collaborative Research Center SFB 910, project B6
As cold as a fish? Relationships between the Dark Triad personality traits and affective experience during the day: A day reconstruction study
The Dark Triad of personality is a cluster of three socially aversive personality traits: Machiavellianism,
narcissism and psychopathy. These traits are associated with a selfish, aggressive
and exploitative interpersonal strategy. The objective of the current study was to
establish relationships between the Dark Triad traits (and their dimensions) and momentary
affect. Machiavellianism, grandiose narcissism, vulnerable narcissism and the dimensions
of the Triarchic model of psychopathy (namely, boldness, meanness and disinhibition) were
examined. We used the Day Reconstruction Method, which is based on reconstructing
affective states experienced during the previous day. The final sample consisted of 270 university
students providing affective ratings of 3047 diary episodes. Analyses using multilevel
modelling showed that only boldness had a positive association with positive affective states
and affect balance, and a negative association with negative affective states. Grandiose
narcissism and its sub-dimensions had no relationship with momentary affect. The other
dark traits were related to negative momentary affect and/or inversely related to positive
momentary affect and affect balance. As a whole, our results empirically demonstrated distinctiveness
of the Dark Triad traits in their relationship to everyday affective states. These
findings are not congruent with the notion that people with the Dark Triad traits, who have a
dispositional tendency to manipulate and exploit others, are generally cold and invulnerable
to negative feelings. The associations between the Dark Triad and momentary affect were
discussed in the contexts of evolutionary and positive psychology, in relation to the role and
adaptive value of positive and negative emotions experienced by individuals higher in
Machiavellianism, narcissism and psychopathy
Effect-directed analysis (EDA) in aquatic ecotoxicology: state of the art and future challenges
Potential of Fusarium wilt-inducing chlamydospores, in vitro behaviour in root exudates and physiology of tomato in biochar and compost amended soil
The Influence of Attributions on the Relevance of Negative Feelings to Personal Satisfaction
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