1,414 research outputs found
ROUSSEAU, Félicien, La croissance solidaire des droits de l’homme. Un retour aux sources de l’éthique.
Organocatalytic Michael addition to (D)-mannitol-derived enantiopure nitroalkenes: A valuable strategy for the synthesis of densely functionalized chiral molecules
Carbohydrates are abundant renewable resources and are a feedstock for green chemistry and sustainable synthesis of the future. Among the hexoses and the pentoses present in biomass, mannitol was selected in the present project as a valuable platform, directly available from the chiral pool, to build highly functionalized molecules. Starting from (R)-2,3-O-cyclohexylidene glyceraldehyde, which is easily prepared in a large scale from D-mannitol, an enantiopure chiral nitro alkene was prepared by reaction with nitromethane, and its reactivity studied. Organocatalytic Michael addition of dimethyl malonate, \u3b2-keto esters, and other nucleophiles on the nitro alkene afforded high stereoselectivity and densely functionalized chiral molecules, which were further synthetically developed, leading to five-membered lactones and bicyclic lactams. Preliminary studies showed that the metal-free catalytic reaction on the chiral nitro alkene can be performed under continuous flow conditions, thus enabling the use of (micro)mesofluidic systems for the preparation of enantiomerically pure organic molecules from the chiral pool
WASP-23b: a transiting hot Jupiter around a K dwarf and its Rossiter-McLaughlin effect
We report the discovery of a new transiting planet in the Southern
Hemisphere. It has been found by the WASP-south transit survey and confirmed
photometrically and spectroscopically by the 1.2m Swiss Euler telescope, LCOGT
2m Faulkes South Telescope, the 60 cm TRAPPIST telescope and the ESO 3.6m
telescope. The orbital period of the planet is 2.94 days. We find it is a gas
giant with a mass of 0.88 \pm 0.10 Mj and a radius estimated at 0.96 \pm 0.05
Rj . We have also obtained spectra during transit with the HARPS spectrograph
and detect the Rossiter-McLaughlin effect despite its small amplitude. Because
of the low signal to noise of the effect and of a small impact parameter we
cannot place a constraint on the projected spin-orbit angle. We find two
confiicting values for the stellar rotation. Our determination, via spectral
line broadening gives v sin I = 2.2 \pm 0.3 km/s, while another method, based
on the activity level using the index log R'HK, gives an equatorial rotation
velocity of only v = 1.35 \pm 0.20 km/s. Using these as priors in our analysis,
the planet could either be misaligned or aligned. This should send strong
warnings regarding the use of such priors. There is no evidence for
eccentricity nor of any radial velocity drift with time.Comment: 13 pages, 8 figures, 7 tables, accepted for publication in A&
Teologija o »strukturama«
De sic dictis ,,structuris" in praesenti agitur. Non analysis termini, non quarumcumque structurarumarum sors interest, attentionem movet potius illa cmae ,,desacratum ac illa quae ,,sacrum" vult christianisum. Certe hic distinctionem inter sacrum (sanctum) et profanum-mundanum numquam abigit. Sive somniando Deum mortuum, sive consilium dando agendum ac si Deus non existeret, in eumdem impingitur lapidem: in negationem sanae metaphysicae, in evacuationem theologiae, in reductionem ad nihilum ipsius Evangelii. Dices, numquid scriptores Deum mortuum profitentes vel Deum in Christo disparuisse blasphemantes digni sunt ut audiantur vel legantur? Libentius dicerem hoc iam non intra limites scientiae sistere verum in campum ethicae: ac moralis transire. Miranda patientia auctor veritatis semitam ostendit
Non-detection of Contamination by Stellar Activity in the Spitzer Transit Light Curves of TRAPPIST-1
We apply the transit light curve self-contamination technique of Morris et
al. (2018) to search for the effect of stellar activity on the transits of the
ultracool dwarf TRAPPIST-1 with 2018 Spitzer photometry. The self-contamination
method fits the transit light curves of planets orbiting spotted stars,
allowing the host star to be a source of contaminating positive or negative
flux which influences the transit depths but not the ingress/egress durations.
We find that none of the planets show statistically significant evidence for
self-contamination by bright or dark regions of the stellar photosphere.
However, we show that small-scale magnetic activity, analogous in size to the
smallest sunspots, could still be lurking in the transit photometry undetected.Comment: Accepted for publication in ApJ
Sexual harassment: The climate for women faculty
This is a study of the organizational climate for sexual harassment for university faculty, specifically, women faculty. Much of the current sexual harassment research in a university setting is focused on the experiences of college students. This study includes a collection of data about the perceptions of organizational climate for sexual harassment and perceptions of policies and procedures as well as practices concerning unwanted sex-related experiences encountered by university faculty. This research is needed because there is a lack of available literature concerning the sexual harassment of women faculty and the corresponding organizational climate
WISE J072003.20-084651.2: An Old and Active M9.5 + T5 Spectral Binary 6 pc from the Sun
[Abridged] We report observations of the recently discovered, nearby late-M
dwarf WISE J072003.20-084651.2. Astrometric measurements obtained with TRAPPIST
improve the distance measurement to 6.01.0 pc and confirm the low
tangential velocity (3.50.6 km/s) reported by Scholz. Low-resolution
optical spectroscopy indicates a spectral type of M9.5 and prominent H
emission ( = -4.680.06), but no evidence of subsolar
metallicity or Li I absorption. Near-infrared spectroscopy reveals subtle
peculiarities indicating the presence of a T5 binary companion, and
high-resolution laser guide star adaptive optics imaging reveals a faint
(H = 4.1) candidate source 0"14 (0.8 AU) from the primary. We measure a
stable radial velocity of +83.80.3 km/s, indicative of old disk kinematics
and consistent with the angular separation of the possible companion. We
measure a projected rotational velocity of v sin i = 8.00.5 km/s, and find
evidence of low-level variability (~1.5%) in a 13-day TRAPPIST lightcurve, but
cannot robustly constrain the rotational period. We also observe episodic
changes in brightness (1-2%) and occasional flare bursts (4-8%) with a 0.8%
duty cycle, and order-of-magnitude variations in H line strength.
Combined, these observations reveal WISE J0720-0846 to be an old, very low-mass
binary whose components straddle the hydrogen burning minimum mass, and whose
primary is a relatively rapid rotator and magnetically active. It is one of
only two known binaries among late M dwarfs within 10 pc of the Sun, both
harboring a mid T-type brown dwarf companion. While this specific configuration
is rare (1.4% probability), roughly 25% of binary companions to late-type M
dwarfs in the local population are likely low-temperature T or Y brown dwarfs.Comment: 18 pages, 23 figures; accepted for publication in A
WASP-50b: a hot Jupiter transiting a moderately active solar-type star
We report the discovery by the WASP transit survey of a giant planet in a
close orbit (0.0295+-0.0009 AU) around a moderately bright (V=11.6, K=10) G9
dwarf (0.89+-0.08 M_sun, 0.84+-0.03 R_sun) in the Southern constellation
Eridanus. Thanks to high-precision follow-up photometry and spectroscopy
obtained by the telescopes TRAPPIST and Euler, the mass and size of this
planet, WASP-50b, are well constrained to 1.47+-0.09 M_jup and 1.15+-0.05
R_jup, respectively. The transit ephemeris is 2455558.6120 (+-0.0002) + N x
1.955096 (+-0.000005) HJD_UTC. The size of the planet is consistent with basic
models of irradiated giant planets. The chromospheric activity (log R'_HK =
-4.67) and rotational period (P_rot = 16.3+-0.5 days) of the host star suggest
an age of 0.8+-0.4 Gy that is discrepant with a stellar-evolution estimate
based on the measured stellar parameters (rho_star = 1.48+-0.10 rho_sun, Teff =
5400+-100 K, [Fe/H]= -0.12+-0.08) which favours an age of 7+-3.5 Gy. This
discrepancy could be explained by the tidal and magnetic influence of the
planet on the star, in good agreement with the observations that stars hosting
hot Jupiters tend to show faster rotation and magnetic activity (Pont 2009;
Hartman 2010). We measure a stellar inclination of 84 (-31,+6) deg,
disfavouring a high stellar obliquity. Thanks to its large irradiation and the
relatively small size of its host star, WASP-50b is a good target for
occultation spectrophotometry, making it able to constrain the relationship
between hot Jupiters' atmospheric thermal profiles and the chromospheric
activity of their host stars proposed by Knutson et al. (2010).Comment: 9 pages, 8 figures. Accepted for publication in Astronomy &
Astrophysic
A Monitoring Campaign for Luhman 16AB. I. Detection of Resolved Near-Infrared Spectroscopic Variability
[abbreviated] We report resolved near-infrared spectroscopic monitoring of
the nearby L dwarf/T dwarf binary WISE J104915.57-531906.1AB (Luhman 16AB), as
part of a broader campaign to characterize the spectral energy distribution and
temporal variability of this system. A continuous 45-minute sequence of
low-resolution IRTF/SpeX data spanning 0.8-2.4 micron were obtained, concurrent
with combined-light optical photometry with ESO/TRAPPIST. Our spectral
observations confirm the flux reversal of this binary, and we detect a
wavelength-dependent decline in the relative spectral fluxes of the two
components coincident with a decline in the combined-light optical brightness
of the system over the course of the observation. These data are successfully
modeled as a combination of brightness and color variability in the T0.5 Luhman
16B, consistent cloud variations; and no significant variability in L7.5 Luhman
16A. We estimate a peak-to-peak amplitude of 13.5% at 1.25 micron over the full
lightcurve. Using a two-spot brightness temperature model, we infer an average
cloud covering fraction of ~30-55% for Luhman 16B, varying by 15-30% over a
rotation period. A Rhines scale interpretation for the size of the variable
features explains an apparent correlation between period and amplitude for
three highly variable T dwarfs, and predicts relatively fast winds (1-3 km/s)
for Luhman 16B consistent with lightcurve evolution on an advective time scale
(1-3 rotation periods). Our observations support the model of a patchy
disruption of the mineral cloud layer as a universal feature of the L dwarf/T
dwarf transition.Comment: 11 pages, 7 figures; accepted for publication in Astrophysical
Journa
- …