6,704 research outputs found
The HARPS search for southern extrasolar planets. XXIII. 8 planetary companions to low-activity solar-type stars
In this paper, we present our HARPS radial-velocity data for eight
low-activity solar-type stars belonging to the HARPS volume-limited sample:
HD6718, HD8535, HD28254, HD290327, HD43197, HD44219, HD148156, and HD156411.
Keplerian fits to these data reveal the presence of low-mass companions around
these targets. With minimum masses ranging from 0.58 to 2.54 MJup, these
companions are in the planetary mass domain. The orbital periods of these
planets range from slightly less than one to almost seven years. The eight
orbits presented in this paper exhibit a wide variety of eccentricities: from
0.08 to above 0.8.Comment: 8 pages, 2 figures, accepted for publication in A&
The development of doctoral degree curriculum in England: Perspectives from professional doctoral degree graduates
The paper investigates two issues surrounding the field of higher education leadership, particularly in doctoral education, namely the reasons why potential doctoral students decided to enroll in a professional doctorate instead of a traditional Doctor of Philosophy (PhD) and how did professional doctorate status enhance its graduates’ professional development and career promotion. Guided by the Social Cognitive Career Theory (SCCT), 20 professional doctorate graduates who are members of a professional association in London were invited as participants. The paper discovers that in the view of professional doctorate graduates, the program offers the flexibility for professionals to enjoy the rigorous education at doctoral level. Second, the curriculum of the professional doctorate allows graduates to apply both theories and practical applications into their current workplace directly. Third, the rich supports from lecturers enhancing the prosperity of professional doctorate graduates’ life experience. This study provides solid evidence and recommendation for university administrators, policy makers, organizational employers, and potential doctoral students in the United Kingdom and other Anglophone countries to understand the learning outcomes and gained skills of professional doctorates. Keywords: career counseling; doctoral student experience; professional doctorate; qualitativ
The HARPS search for southern extrasolar planets XXI. Three new giant planets orbiting the metal-poor stars HD5388, HD181720, and HD190984
We present the discovery of three new giant planets around three
metal-deficient stars: HD5388b (1.96M_Jup), HD181720b (0.37M_Jup), and
HD190984b (3.1M_Jup). All the planets have moderately eccentric orbits (ranging
from 0.26 to 0.57) and long orbital periods (from 777 to 4885 days). Two of the
stars (HD181720 and HD190984) were part of a program searching for giant
planets around a sample of ~100 moderately metal-poor stars, while HD5388 was
part of the volume-limited sample of the HARPS GTO program. Our discoveries
suggest that giant planets in long period orbits are not uncommon around
moderately metal-poor stars.Comment: Accepted for publication in A&A (replaced by version with minor
language corrections
SUP&R DSS: A sustainability-based decision support system for road pavements
Road pavement community members are increasingly becoming aware of the need to incorporating the principles of sustainable development into the sector. Policies are also going in this direction and as a consequence in the recent years researchers and practitioners are coming up with new materials, technologies and practices designed to reduce the negative impacts of their activities in the surroundings. Within this framework the road pavements sector is witnessing a paradigm shift towards the development of pavement technologies incorporating high-content of recycled materials, as well as best practices to decrease the overall carbon footprint. These are all promising solutions that to the most can sound as sustainable practices. However the whole road pavement community is still investigating methodologies and tools to define what actually sustainable means and thereby performing a sustainable decision-making. It is within this context that the need of a sustainability-based decision support system (DSS) that could help road pavement engineers at the design stage was identified and is here presented. The Sustainable Pavements & Railways DSS (SUP&R DSS) relies on a multi-criteria decision analysis (MCDA) method to rank the sustainability of alternatives. It applies life cycle-based approaches to quantify the values of a set of indicators purposely and methodologically selected to capture the cause- effect link between the general concepts of the three wellbeing dimensions of sustainability, i.e., environmental, economic and social, and the infrastructure construction and maintenance practice. Furthermore, the system allows selecting different weighting for the indicators but offers also a default set of values derived from a survey conducted with over 50 stakeholders in Europe and beyond. Together with the development, structure and features of the SUP&R DSS, this paper present its applicability by means of a case study aiming at identifying the most sustainable asphalt mixture for wearing courses. Several promising options for flexible road pavements were selected, ranging from low to hot temperature asphalt. The results show that a foamed warm mix asphalt mixture with a reclaimed asphalt pavement content of 50% is the most sustainable among the competing alternatives. Furthermore, a sensitivity analysis conducted to investigate the influence of the indicators weights, the parameters of the MCDA method and the long-term performance of the alternative asphalt mixtures on the stability of the ranking showed that its first position in the ranking remained unaffected
Bell's inequality without alternative settings
A suitable generalized measurement described by a 4-element positive
operator-valued measure (POVM) on each particle of a two-qubit system in the
singlet state is, from the point of view of Einstein, Podolsky, and Rosen's
(EPR's) criterion of elements of reality, equivalent to a random selection
between two alternative projective measurements. It is shown that an
EPR-experiment with a fixed POVM on each particle provides a violation of
Bell's inequality without requiring local observers to choose between the
alternatives. This approach could be useful for designing a loophole-free test
of Bell's inequality.Comment: LaTeX, 13 pages, 3 figure
A Novel Root-Knot Nematode Resistance QTL on Chromosome Vu01 in Cowpea.
The root-knot nematode (RKN) species Meloidogyne incognita and M. javanica cause substantial root system damage and suppress yield of susceptible cowpea cultivars. The narrow-based genetic resistance conferred by the Rk gene, present in some commercial cultivars, is not effective against Rk-virulent populations found in several cowpea production areas. The dynamics of virulence within RKN populations require a broadening of the genetic base of resistance in elite cowpea cultivars. As part of this goal, F1 and F2 populations from the cross CB46-Null (susceptible) x FN-2-9-04 (resistant) were phenotyped for M. javanica induced root-galling (RG) and egg-mass production (EM) in controlled growth chamber and greenhouse infection assays. In addition, F[Formula: see text] families of the same cross were phenotyped for RG on field sites infested with Rk-avirulent M. incognita and M. javanica The response of F1 to RG and EM indicated that resistance to RKN in FN-2-9-04 is partially dominant, as supported by the degree of dominance in the F2 and F[Formula: see text] populations. Two QTL associated with both RG and EM resistance were detected on chromosomes Vu01 and Vu04. The QTL on Vu01 was most effective against aggressive M. javanica, whereas both QTL were effective against avirulent M. incognita Allelism tests with CB46 x FN-2-9-04 progeny indicated that these parents share the same RKN resistance locus on Vu04, but the strong, broad-based resistance in FN-2-9-04 is conferred by the additive effect of the novel resistance QTL on Vu01. This novel resistance in FN-2-9-04 is an important resource for broadening RKN resistance in elite cowpea cultivars
The HARPS search for southern extra-solar planets. IX. Exoplanets orbiting HD 100777, HD 190647, and HD 221287
The HARPS high-resolution high-accuracy spectrograph is offered to the
astronomical community since the second half of 2003. Since then, we have been
using this instrument for monitoring radial velocities of a large sample of
Solar-type stars (~1400 stars) in order to search for their possible low-mass
companions. Amongst the goals of our survey, one is to significantly increase
the number of detected extra-solar planets in a volume-limited sample to
improve our knowledge of their orbital elements distributions and thus obtain
better constraints for planet-formation models.
In this paper, we present the HARPS radial-velocity data and orbital
solutions for 3 Solar-type stars: HD 100777, HD 190647, and HD 221287. The
radial-velocity data of HD 100777 is best explained by the presence of a 1.1
M_Jup planetary companion on a 384--day eccentric orbit (e=0.36). The orbital
fit obtained for the slightly evolved star HD 190647 reveals the presence of a
long-period (P=1038 d) 1.9 M_Jup planetary companion on a moderately eccentric
orbit (e=0.18). HD 221287 is hosting a 3.1 M_Jup planet on a 456--day orbit.
The shape of this orbit is not very well constrained because of our non-optimal
temporal coverage and because of the presence of abnormally large residuals. We
find clues for these large residuals to result from spectral line profile
variations probably induced by stellar activity related processes.Comment: 7 pages, 4 figures, RV data added in paper. A&A in pres
The HARPS search for southern extrasolar planets: XXXIII. New multi-planet systems in the HARPS volume limited sample: a super-Earth and a Neptune in the habitable zone
The vast diversity of planetary systems detected to date is defying our
capability of understanding their formation and evolution. Well-defined
volume-limited surveys are the best tool at our disposal to tackle the problem,
via the acquisition of robust statistics of the orbital elements. We are using
the HARPS spectrograph to conduct our survey of ~850 nearby solar-type stars,
and in the course of the past nine years we have monitored the radial velocity
of HD103774, HD109271, and BD-061339. In this work we present the detection of
five planets orbiting these stars, with m*sin(i) between 0.6 and 7 Neptune
masses, four of which are in two multiple systems, comprising one super-Earth
and one planet within the habitable zone of a late-type dwarf. Although for
strategic reasons we chose efficiency over precision in this survey, we have
the capability to detect planets down to the Neptune and super-Earth mass
range, as well as multiple systems, provided that enough data points are made
available.Comment: 7 pages, 14 figures, accepted for publication by A&A, 04-01-201
The HARPS search for southern extra-solar planets. XX. Planets around the active star BD-08:2823
We report the detection of a planetary system around BD-08:2823, that
includes at least one Uranus-mass planet and one Saturn-mass planet. This
discovery serendipitously originates from a search for planetary transits in
the Hipparcos photometry database. This program preferentially selected active
stars and did not allow the detection of new transiting planets. It allowed
however the identification of the K3V star BD-08:2823 as a target harboring a
multiplanet system, that we secured and characterized thanks to an intensive
monitoring with the HARPS spectrograph at the 3.6-m ESO telescope in La Silla.
The stellar activity level of BD-08:2823 complicates the analysis but does not
prohibit the detection of two planets around this star. BD-08:2823b has a
minimum mass of 14.4+/-2.1 M_Earth and an orbital period of 5.60 days, whereas
BD-08:2823c has a minimum mass of 0.33+/-0.03 M_Jup and an orbital period of
237.6 days. This new system strengthens the fact that low-mass planets are
preferentially found in multiplanetary systems, but not around high-metallicity
stars as this is the case for massive planets. It also supports the belief that
active stars should not be neglected in exoplanet searches, even when searching
for low-mass planets.Comment: 10 pages, 8 figures, 3 tables, accepted for publication in A&
Chemical abundances of 1111 FGK stars from the HARPS GTO planet search program.Galactic stellar populations and planets
We performed a uniform and detailed abundance analysis of 12 refractory
elements (Na, Mg, Al, Si, Ca, Ti, Cr, Ni, Co, Sc, Mn and V) for a sample of
1111 FGK dwarf stars from the HARPS GTO planet search program. 109 of these
stars are known to harbour giant planetary companions and 26 stars are hosting
exclusively Neptunians and super-Earths. The main goals of this paper are i) to
investigate whether there are any differences between the elemental abundance
trends for stars of different stellar populations; ii) to characterise the
planet host and non-host samples in term of their [X/H]. The extensive study of
this sample, focused on the abundance differences between stars with and
without planets will be presented in a parallel paper. The equivalent widths of
spectral lines are automatically measured from HARPS spectra with the ARES
code. The abundances of the chemical elements are determined using a LTE
abundance analysis relative to the Sun, with the 2010 revised version of the
spectral synthesis code MOOG and a grid of Kurucz ATLAS9 atmospheres. To
separate the Galactic stellar populations we applied both a purely kinematical
approach and a chemical method. We found that the chemically separated (based
on the Mg, Si, and Ti abundances) thin and thick discs are also chemically
disjunct for Al, Sc, Co and Ca. Some bifurcation might also exist for Na, V,
Ni, and Mn, but there is no clear boundary of their [X/Fe] ratios. We confirm
that an overabundance in giant-planet host stars is clear for all the studied
elements.We also confirm that stars hosting only Neptunian-like planets may be
easier to detect around stars with similar metallicities as non-planet hosts,
although for some elements (particulary alpha-elements) the lower limit of
[X/H] are very abrupt.Comment: 14 pages, 12 figures, 6 tables. accepted for publication in Astronomy
& Astrophysic
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