2,594 research outputs found
Low-mass star formation in CG1: a diffraction limited search for pre-main sequence stars next to NX Puppis
Using adaptive optics at the ESO 3.6m telescope, we obtained diffraction
limited JHK-images of the region around the Herbig AeBe star NX Pup. We clearly
resolved the close companion (sep. 0.128") to NX Pup -- originally discovered
by HST -- and measured its JHK magnitudes. A third object at a separation of
7.0" from NX Pup was identified as a classical T Tauri star so that NX Pup may
in fact form a hierarchical triple system. We discuss the evolutionary status
of these stars and derive estimates for their spectral types, luminosities,
masses and ages.Comment: Latex using l-aa-ps.sty with links to 5 postscript figures. Complete
postscript version also available at http://lucky.astro.uni-wuerzburg.de/
Accepted for publication in A&
Experimental optimization of exposure index and quality of service in WLAN networks
This paper presents the first real-life optimization of the Exposure Index (EI). A genetic optimization algorithm is developed and applied to three real-life Wireless Local Area Network scenarios in an experimental testbed. The optimization accounts for downlink, uplink and uplink of other users, for realistic duty cycles, and ensures a sufficient Quality of Service to all users. EI reductions up to 97.5% compared to a reference configuration can be achieved in a downlink-only scenario, in combination with an improved Quality of Service. Due to the dominance of uplink exposure and the lack of WiFi power control, no optimizations are possible in scenarios that also consider uplink traffic. However, future deployments that do implement WiFi power control can be successfully optimized, with EI reductions up to 86% compared to a reference configuration and an EI that is 278 times lower than optimized configurations under the absence of power control
Hydrogeologisch onderzoek van het terrein en het vliegasstort van de elektrische centrale Ruien in het bestek van een milieu-effectrapport (ombouw groepen 5 en 6)
Automating Data Science: Prospects and Challenges
Given the complexity of typical data science projects and the associated
demand for human expertise, automation has the potential to transform the data
science process.
Key insights:
* Automation in data science aims to facilitate and transform the work of
data scientists, not to replace them.
* Important parts of data science are already being automated, especially in
the modeling stages, where techniques such as automated machine learning
(AutoML) are gaining traction.
* Other aspects are harder to automate, not only because of technological
challenges, but because open-ended and context-dependent tasks require human
interaction.Comment: 19 pages, 3 figures. v1 accepted for publication (April 2021) in
Communications of the AC
Pilot study to develop and test palliative care quality indicators for nursing homes
An increasingly frail population in nursing homes accentuates the need for high quality care at the end of life and better access to palliative care in this context. Implementation of palliative care and its outcomes can be monitored by using quality indicators. Therefore, we developed a quality indicator set for palliative care in nursing homes and a tailored measurement procedure while using a mixed-methods design. We developed the instrument in three phases: (1) literature search, (2) interviews with experts, and (3) indicator and measurement selection by expert consensus (RAND/UCLA). Second, we pilot tested and evaluated the instrument in nine nursing homes in Flanders, Belgium. After identifying 26 indicators in the literature and expert interviews, 19 of them were selected through expert consensus. Setting-specific themes were advance care planning, autonomy, and communication with family. The quantitative and qualitative analyses showed that the indicators were measurable, had good preliminary face validity and discriminative power, and were considered to be useful in terms of quality monitoring according to the caregivers. The quality indicators can be used in a large implementation study and process evaluation in order to achieve continuous monitoring of the access to palliative care for all of the residents in nursing homes
Survey of fungal diversity in silages supplied to dairy cattle in Belgium over a two-year period
The fungal diversity in silages for dairy cattle feeding has been assessed by purification and identification of 966 isolates collected in silages during the two 2006 and 2007 winter storage/feed-out periods from farms localized in various geographic regions in Belgium. The relevant fungal species in silos were P. paneum and P. roqueforti (18.2 % and 14.5 % of total isolates, respectively). The proportion between the two species varied significantly from 2006 to 2007 (P<0.05) depending on the type of forage crop. The prevalence of P. paneum in Belgium compared to results in other countries is of major importance due to the mycotoxigenic capacity of this species. Information on numerous aspects of silage making process and silo management showed that neither the crop rotation, the date and weather at harvest, the use of additives, the feeding rate, the type and dimension of silo, the covering used nor the forage chopping length at ensiling could be significantly correlated to the fungal species composition isolated in farm silages. There were also no significant relationships between the chemico-fermentative parameters tested (dry matter, pH, NH3 content, concentration of lactic, acetic and butyric acids) and the fungal species composition in silages. The prevalent fungi were tolerant of the wide ranges of conditions found in the farm silages with year-to-year variations. Survey of Fungal Diversity in Silages Supplied to Dairy Cattle in Belgium Over a Two-Year Period. Available from: https://www.researchgate.net/publication/313255127_Survey_of_Fungal_Diversity_in_Silages_Supplied_to_Dairy_Cattle_in_Belgium_Over_a_Two-Year_Period [accessed Jul 24, 2017]
Specific implications of the HIV-1 nucleocapsid zinc fingers in the annealing of the primer binding site complementary sequences during the obligatory plus strand transfer
Synthesis of the HIV-1 viral DNA by reverse transcriptase involves two obligatory strand transfer reactions. The second strand transfer corresponds to the annealing of the (−) and (+) DNA copies of the primer binding site (PBS) sequence which is chaperoned by the nucleocapsid protein (NCp7). NCp7 modifies the (+)/(−)PBS annealing mechanism by activating a loop–loop kissing pathway that is negligible without NCp7. To characterize in depth the dynamics of the loop in the NCp7/PBS nucleoprotein complexes, we investigated the time-resolved fluorescence parameters of a (−)PBS derivative containing the fluorescent nucleoside analogue 2-aminopurine at positions 6, 8 or 10. The NCp7-directed switch of (+)/(−)PBS annealing towards the loop pathway was associated to a drastic restriction of the local DNA dynamics, indicating that NCp7 can ‘freeze’ PBS conformations competent for annealing via the loops. Moreover, the modifications of the PBS loop structure and dynamics that govern the annealing reaction were found strictly dependent on the integrity of the zinc finger hydrophobic platform. Our data suggest that the two NCp7 zinc fingers are required to ensure the specificity and fidelity of the second strand transfer, further underlining the pivotal role played by NCp7 to control the faithful synthesis of viral HIV-1 DNA
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