372 research outputs found
The stellar content of low redshift BL Lac host galaxies from multicolour imaging
We present B-band imaging of 18 low redshift (z<0.3) BL Lac objects for which
their host galaxies were previously resolved in the R-band and the
near-infrared H-band. For a subset of the objects, also U- and V-band imaging
is presented. These data are used to investigate the blue-red-near-infrared
colours and the colour gradients of the host galaxies of BL Lacs in comparison
with other elliptical galaxies with and without nuclear activity. In all cases
galaxies are well represented by an elliptical model, with average absolute
magnitude M_B=-21.6+-0.7 and average scale length R_e=7.6+-3.2 kpc. The
best-fit B-band Kormendy relation is in reasonable agreement with that obtained
for normal ellipticals and radio galaxies. This structural and dynamical
similarity indicates that all massive elliptical galaxies can experience
nuclear activity without significant perturbation of their global structure.
The distributions of the integrated blue/near-infrared colour (with average
B-H=3.5+-0.5) and colour gradient (with average Delta(B-R)/Delta(log
r)=-0.14+-0.75) of the BL Lac hosts are much wider than those for normal
ellipticals, and most BL Lac objects have bluer hosts and/or steeper colour
gradients than those in normal ellipticals. The blue colours are likely caused
by a young stellar population component, and indicates a link between star
formation caused by an interaction/merging event and the onset of the nuclear
activity. This result is corroborated by stellar population modelling,
indicating a presence of young/intermediate age populations in the majority of
the sample, in agreement with low redshift quasar hosts. The lack of strong
signs of interaction may require a significant time delay between the event
with associated star formation episodes and the start of the nuclear activity.Comment: 16 pages, 10 figure
OGLE-2005-BLG-018: Characterization of Full Physical and Orbital Parameters of a Gravitational Binary Lens
We present the analysis result of a gravitational binary-lensing event
OGLE-2005-BLG-018. The light curve of the event is characterized by 2 adjacent
strong features and a single weak feature separated from the strong features.
The light curve exhibits noticeable deviations from the best-fit model based on
standard binary parameters. To explain the deviation, we test models including
various higher-order effects of the motions of the observer, source, and lens.
From this, we find that it is necessary to account for the orbital motion of
the lens in describing the light curve. From modeling of the light curve
considering the parallax effect and Keplerian orbital motion, we are able to
measure not only the physical parameters but also a complete orbital solution
of the lens system. It is found that the event was produced by a binary lens
located in the Galactic bulge with a distance kpc from the Earth.
The individual lens components with masses and are separated with a semi-major axis of AU and
orbiting each other with a period yr. The event demonstrates
that it is possible to extract detailed information about binary lens systems
from well-resolved lensing light curves.Comment: 19 pages, 6 figure
The Cyst-Theca Relationship Of The Dinoflagellate Cyst Trinovantedinium Pallidifulvum, With Erection Of Protoperidinium Lousianensis Sp Nov And Their Phylogenetic Position Within The Conica Group
We establish the cyst-theca relationship of the dinoflagellate cyst species Trinovantedinium pallidifulvum Matsuoka 1987 based on germination experiments of specimens isolated from the Gulf of Mexico. We show that the motile stage is a new species, designated as Protoperidinium louisianensis. We also determine its phylogenetic position based on single-cell polymerase chain reaction (PCR) of a single cell germinated from the Gulf of Mexico cysts. To further refine the phylogeny, we determined the large subunit (LSU) sequence through single-cell PCR of the cyst Selenopemphix undulata isolated from Brentwood Bay (Saanich Inlet, BC, Canada). The phylogeny shows that P. louisianensis is closest to P. shanghaiense, the motile stage of T. applanatum, and is consistent with the monophyly of the genus Trinovantedinium. Selenopemphix undulata belongs to a different clade than Selenopemphix quanta (alleged cyst of P. conicum), suggesting that the genus Selenopemphix is polyphyletic. Trinovantedinium pallidifulvum is widely distributed with occurrences in the Gulf of Mexico, the North Atlantic, the northeast Pacific and southeast Asia. In addition, we illustrate the two other extant species, Trinovantedinium applanatum and Trinovantedinium variabile, and two morphotypes of Trinovantedinium. Geochemical analyses of the cyst wall of T. pallidifulvum indicate the presence of amide groups in agreement with other heterotrophic dinoflagellate species, although the cyst wall of T. pallidifulvum also includes some unique features
Disciplined into good conduct : Gender constructions of users in a municipal psychiatric context in Sweden
Aims and objectives To examine how gendered discursive norms and notions of masculinity and femininity were (re)produced in professional conversations about users of long‐term municipality psychiatric care. Focus is on the staff’s use of language in relation to gender constructions. Background Psychiatric care in Sweden has undergone tremendous changes in recent decades from custodian care in large hospitals to a care mainly located in a municipal context. People who need psychiatric care services often live in supporting houses. In municipal psychiatric care, staff conduct weekly professional meetings to discuss daily matters and the users’ needs. Official reports of the Swedish government have shown that staff in municipal care services treat disabled women and men differently. Studies exploring gender in relation to users of long‐term psychiatric care in municipalities have problematised the care and how staff, through language, construct users’ gender. Therefore, language used by staff is a central tool for ascribing different gender identities of users. Design The content of speech derived from audio recordings were analysed using Foucauldian discursive analysis. The COREQ checklist was used in this article. Results The results indicate that by relying on gender discourses, staff create a conditional care related to how the users should demonstrate good conduct. In line with that, an overall discourse was created: Disciplined into good conduct. It was underpinned by three discourses inherent therein: The unreliable drinker and the confession, Threatened dignity, Doing different femininities. Conclusion The community psychiatric context generates a discourse of conduct in which staff, via spoken language (re)produces gendered patterns and power imbalances as a means to manage daily work routines. Such practices of care, in which constant, nearly panoptic, control despite the intention to promote autonomy, urgently require problematising current definitions of good conduct and normality.Peer reviewe
An analogue of the Prolactin Releasing Peptide reduces obesity and promotes adult neurogenesis
Hypothalamic Adult Neurogenesis (hAN) has been implicated in regulating energy homeostasis. Adult-generated neurons and adult Neural Stem Cells (aNSCs) in the hypothalamus control food intake and body weight. Conversely, diet-induced obesity (DIO) by high fat diets (HFD) exerts adverse influence on hAN. However, the effects of anti-obesity compounds on hAN are not known. To address this, we administered a lipidized analogue of an anti-obesity neuropeptide, Prolactin Releasing Peptide (PrRP), so-called LiPR, to mice. In the HFD context, LiPR rescued the survival of adult-born hypothalamic neurons and increased the number of aNSCs by reducing their activation. LiPR also rescued the reduction of immature hippocampal neurons and modulated calcium dynamics in iPSC-derived human neurons. In addition, some of these neurogenic effects were exerted by another anti-obesity compound, Liraglutide. These results show for the first time that anti-obesity neuropeptides influence adult neurogenesis and suggest that the neurogenic process can serve as a target of anti-obesity pharmacotherapy
Impact Factor: outdated artefact or stepping-stone to journal certification?
A review of Garfield's journal impact factor and its specific implementation
as the Thomson Reuters Impact Factor reveals several weaknesses in this
commonly-used indicator of journal standing. Key limitations include the
mismatch between citing and cited documents, the deceptive display of three
decimals that belies the real precision, and the absence of confidence
intervals. These are minor issues that are easily amended and should be
corrected, but more substantive improvements are needed. There are indications
that the scientific community seeks and needs better certification of journal
procedures to improve the quality of published science. Comprehensive
certification of editorial and review procedures could help ensure adequate
procedures to detect duplicate and fraudulent submissions.Comment: 25 pages, 12 figures, 6 table
Total costs and benefits of biomass in selected regions of the European Union
The paper describes results of the BioCosts project in which a comprehensive analysis of the economic and environmental performance of the energy use of biomass was carried out for selected existing facilities throughout the European Union. It is demonstrated that the appropriately organized use of biofuels has significant environmental advantages compared to the use of fossil fuels. Mitigation of global warming is the largest single incentive to use biofuels. However, only a few technologies are economically competitive under prevailing conditions, while others lead to up to 100% higher energy production costs than fossil fuels. Employment effects of using biofuels are small but positive.http://www.sciencedirect.com/science/article/B6V2S-41JM99D-4/1/514a3253589af4590f84544e2966bcb
Governance Conditions for Improving Quality Drinking Water Resources: the Need for Enhancing Connectivity
Realising the water quality objectives of the European Water Framework Directive have appeared to stagnate over the last decade all across Europe because of their highly complex nature. In the literature, interactive governance approaches tend to be regarded as the best way of dealing with complex water issues, but so far little empirical evidence has been reported on this perspective in regard to water quality issues. In this paper we have analysed how conditions of governance contribute to the realisation of water quality objectives at different types of drinking water resources in the Netherlands. The analysis demonstrates the importance of addressing different hydrological scales, institutional levels and sectors and thus enhance connectivity in order to improve water quality. The two other important conditions of governance approaches for water quality improvement which were identified are the use of joint fact-finding to gain a shared perception of risks, and the use of explicit decision-making and close monitoring of outcomes (re. water quality improvement), both of which contribute to this enhanced connectivity
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