In the Shadow of the Transiting Disk: Imaging epsilon Aurigae in Eclipse

Eclipses of the single-line spectroscopic binary star, epsilon Aurigae, provide an opportunity to study the poorly-defined companion. We used the MIRC beam combiner on the CHARA array to create interferometric images during eclipse ingress. Our results demonstrate that the eclipsing body is a dark disk that is opaque and tilted, and therefore exclude alternative models for the system. These data constrain the geometry and masses of the components, providing evidence that the F-star is not a massive supergiant star.Comment: As submitted to Nature. Published in Nature April 8, 2010

Stress-Induced Reinstatement of Drug Seeking: 20 Years of Progress

In human addicts, drug relapse and craving are often provoked by stress. Since 1995, this clinical scenario has been studied using a rat model of stress-induced reinstatement of drug seeking. Here, we first discuss the generality of stress-induced reinstatement to different drugs of abuse, different stressors, and different behavioral procedures. We also discuss neuropharmacological mechanisms, and brain areas and circuits controlling stress-induced reinstatement of drug seeking. We conclude by discussing results from translational human laboratory studies and clinical trials that were inspired by results from rat studies on stress-induced reinstatement. Our main conclusions are (1) The phenomenon of stress-induced reinstatement, first shown with an intermittent footshock stressor in rats trained to self-administer heroin, generalizes to other abused drugs, including cocaine, methamphetamine, nicotine, and alcohol, and is also observed in the conditioned place preference model in rats and mice. This phenomenon, however, is stressor specific and not all stressors induce reinstatement of drug seeking. (2) Neuropharmacological studies indicate the involvement of corticotropin-releasing factor (CRF), noradrenaline, dopamine, glutamate, kappa/dynorphin, and several other peptide and neurotransmitter systems in stress-induced reinstatement. Neuropharmacology and circuitry studies indicate the involvement of CRF and noradrenaline transmission in bed nucleus of stria terminalis and central amygdala, and dopamine, CRF, kappa/dynorphin, and glutamate transmission in other components of the mesocorticolimbic dopamine system (ventral tegmental area, medial prefrontal cortex, orbitofrontal cortex, and nucleus accumbens). (3) Translational human laboratory studies and a recent clinical trial study show the efficacy of alpha-2 adrenoceptor agonists in decreasing stress-induced drug craving and stress-induced initial heroin lapse

Expression of Msx-1 is suppressed in bisphosphonate associated osteonecrosis related jaw tissue-etiopathology considerations respecting jaw developmental biology-related unique features

<p>Abstract</p> <p>Background</p> <p>Bone-destructive disease treatments include bisphosphonates and antibodies against the osteoclast differentiator, RANKL (aRANKL); however, osteonecrosis of the jaw (ONJ) is a frequent side-effect. Current models fail to explain the restriction of bisphosphonate (BP)-related and denosumab (anti-RANKL antibody)-related ONJ to jaws. Msx-1 is exclusively expressed in craniofacial structures and pivotal to cranial neural crest (CNC)-derived periodontal tissue remodeling. We hypothesised that Msx-1 expression might be impaired in bisphosphonate-related ONJ. The study aim was to elucidate Msx-1 and RANKL-associated signal transduction (BMP-2/4, RANKL) in ONJ-altered and healthy periodontal tissue.</p> <p>Methods</p> <p>Twenty ONJ and twenty non-BP exposed periodontal samples were processed for RT-PCR and immunohistochemistry. An automated staining-based alkaline phosphatase-anti-alkaline phosphatase method was used to measure the stained cells:total cell-number ratio (labelling index, Bonferroni adjustment). Real-time RT-PCR was performed on ONJ-affected and healthy jaw periodontal samples (n = 20 each) to quantitatively compare Msx-1, BMP-2, RANKL, and GAPDH mRNA levels.</p> <p>Results</p> <p>Semi-quantitative assessment of the ratio of stained cells showed decreased Msx-1 and RANKL and increased BMP-2/4 (all p < 0.05) expression in ONJ-adjacent periodontal tissue. ONJ tissue also exhibited decreased relative gene expression for Msx-1 (p < 0.03) and RANKL (p < 0.03) and increased BMP-2/4 expression (p < 0.02) compared to control.</p> <p>Conclusions</p> <p>These results explain the sclerotic and osteopetrotic changes of periodontal tissue following BP application and substantiate clinical findings of BP-related impaired remodeling specific to periodontal tissue. RANKL suppression substantiated the clinical finding of impaired bone remodelling in BP- and aRANKL-induced ONJ-affected bone structures. Msx-1 suppression in ONJ-adjacent periodontal tissue suggested a bisphosphonate-related impairment in cellular differentiation that occurred exclusively jaw remodelling. Further research on developmental biology-related unique features of jaw bone structures will help to elucidate pathologies restricted to maxillofacial tissue.</p

First observations of separated atmospheric nu_mu and bar{nu-mu} events in the MINOS detector

The complete 5.4 kton MINOS far detector has been taking data since the beginning of August 2003 at a depth of 2070 meters water-equivalent in the Soudan mine, Minnesota. This paper presents the first MINOS observations of nuµ and [overline nu ]µ charged-current atmospheric neutrino interactions based on an exposure of 418 days. The ratio of upward- to downward-going events in the data is compared to the Monte Carlo expectation in the absence of neutrino oscillations, giving Rup/downdata/Rup/downMC=0.62-0.14+0.19(stat.)±0.02(sys.). An extended maximum likelihood analysis of the observed L/E distributions excludes the null hypothesis of no neutrino oscillations at the 98% confidence level. Using the curvature of the observed muons in the 1.3 T MINOS magnetic field nuµ and [overline nu ]µ interactions are separated. The ratio of [overline nu ]µ to nuµ events in the data is compared to the Monte Carlo expectation assuming neutrinos and antineutrinos oscillate in the same manner, giving R[overline nu ][sub mu]/nu[sub mu]data/R[overline nu ][sub mu]/nu[sub mu]MC=0.96-0.27+0.38(stat.)±0.15(sys.), where the errors are the statistical and systematic uncertainties. Although the statistics are limited, this is the first direct observation of atmospheric neutrino interactions separately for nuµ and [overline nu ]µ

Prefrontal cortex output circuits guide reward seeking through divergent cue encoding

The prefrontal cortex is a critical neuroanatomical hub for controlling motivated behaviours across mammalian species. In addition to intra-cortical connectivity, prefrontal projection neurons innervate subcortical structures that contribute to reward-seeking behaviours, such as the ventral striatum and midline thalamus. While connectivity among these structures contributes to appetitive behaviours, how projection-specific prefrontal neurons encode reward-relevant information to guide reward seeking is unknown. Here we use in vivo two-photon calcium imaging to monitor the activity of dorsomedial prefrontal neurons in mice during an appetitive Pavlovian conditioning task. At the population level, these neurons display diverse activity patterns during the presentation of reward-predictive cues. However, recordings from prefrontal neurons with resolved projection targets reveal that individual corticostriatal neurons show response tuning to reward-predictive cues, such that excitatory cue responses are amplified across learning. By contrast, corticothalamic neurons gradually develop new, primarily inhibitory responses to reward-predictive cues across learning. Furthermore, bidirectional optogenetic manipulation of these neurons reveals that stimulation of corticostriatal neurons promotes conditioned reward-seeking behaviour after learning, while activity in corticothalamic neurons suppresses both the acquisition and expression of conditioned reward seeking. These data show how prefrontal circuitry can dynamically control reward-seeking behaviour through the opposing activities of projection-specific cell populations

Observation of Muon Neutrino Disappearance with the MINOS Detectors in the NuMI Neutrino Beam

This Letter reports results from the MINOS experiment based on its initial exposure to neutrinos from the Fermilab NuMI beam. The rates and energy spectra of charged current νμ interactions are compared in two detectors located along the beam axis at distances of 1 and 735 km. With 1.27×1020 120 GeV protons incident on the NuMI target, 215 events with energies below 30 GeV are observed at the Far Detector, compared to an expectation of 336±14 events. The data are consistent with νμ disappearance via oscillations with |Δm322|=2.74-0.26+0.44×10-3  eV2 and sin⁡2(2θ23)>0.87 (68% C.L.)

HAT-P-20b-HAT-P-23b: Four Massive Transiting Extrasolar Planets

We report the discovery of four relatively massive (2–7 M J ) transiting extrasolar planets. HAT-P-20b orbits the moderately bright V = 11.339 K3 dwarf star GSC 1910-00239 on a circular orbit, with a period P = 2 . 875317 ± 0 . 000004 days, transit epoch T c = 2455080 . 92661 ± 0 . 00021 (BJD UTC ), and transit dura- tion 0 . 0770 ± 0 . 0008 days. The host star has a mass of 0 . 76 ± 0 . 03 M , radius of 0 . 69 ± 0 . 02 R , effective temperature 4595 ± 80 K, and metallicity [Fe / H] = +0 . 35 ± 0 . 08. The planetary companion has a mass of 7 . 246 ± 0 . 187 M J and a radius of 0 . 867 ± 0 . 033 R J yielding a mean density of 13 . 78 ± 1 . 50 g cm − 3 . HAT-P-21b orbits the V = 11.685 G3 dwarf star GSC 3013-01229 on an eccentric ( e = 0 . 228 ± 0 . 016) orbit, with a period P = 4 . 124481 ± 0 . 000007 days, transit epoch T c = 2454996 . 41312 ± 0 . 00069, and transit duration 0 . 1530 ± 0 . 0027 days. The host star has a mass of 0 . 95 ± 0 . 04 M , radius of 1 . 10 ± 0 . 08 R , effective temperature 5588 ± 80 K, and metallicity [Fe / H] = +0 . 01 ± 0 . 08. The planetary companion has a mass of 4 . 063 ± 0 . 161 M J and a radius of 1 . 024 ± 0 . 092 R J yielding a mean density of 4 . 68 +1 . 59 − 0 . 99 gcm − 3 . HAT-P-21b is a borderline ob- ject between the pM and pL class planets, and the transits occur near apastron. HAT-P-22b orbits the bright V = 9.732 G5 dwarf star HD 233731 on a circular orbit, with a period P = 3 . 212220 ± 0 . 000009 days, transit epoch T c = 2454930 . 22001 ± 0 . 00025, and transit duration 0 . 1196 ± 0 . 0014 days. The host star has a mass of 0 . 92 ± 0 . 03 M , radius of 1 . 04 ± 0 . 04 R , effective temperature 5302 ± 80 K, and metallicity [Fe / H] = +0 . 24 ± 0 . 08. The planet has a mass of 2 . 147 ± 0 . 061 M J and a compact radius of 1 . 080 ± 0 . 058 R J yielding a mean density of 2 . 11 +0 . 40 − 0 . 29 gcm − 3 . The host star also harbors an M-dwarf companion at a wide separation. Finally, HAT-P-23b orbits the V = 12.432 G0 dwarf star GSC 1632-01396 on a close to circular orbit, with a period P = 1 . 212884 ± 0 . 000002 days, transit epoch T c = 2454852 . 26464 ± 0 . 00018, and transit duration 0 . 0908 ± 0 . 0007 days. The host star has a mass of 1 . 13 ± 0 . 04 M , radius of 1 . 20 ± 0 . 07 R , effective temperature 5905 ± 80 K, and metallicity [Fe / H] = +0 . 15 ± 0 . 04. The planetary companion has a mass of 2 . 090 ± 0 . 111 M J and a radius of 1 . 368 ± 0 . 090 R J yielding a mean density of 1 . 01 ± 0 . 18 g cm − 3 . HAT-P-23b is an inflated and massive hot Jupiter on a very short period orbit, and has one of the shortest characteristic infall times (7 . 5 +2 . 9 − 1 . 8 Myr) before it gets engulfed by the star

HAT-P-32b and HAT-P-33b: Two Highly Inflated Hot Jupiters Transiting High-jitter Stars

We report the discovery of two exoplanets transiting high-jitter stars. HAT-P-32b orbits the bright V = 11.289 late-F–early-G dwarf star GSC 3281-00800, with a period P = 2 . 150008 ± 0 . 000001 d. The stellar and planetary masses and radii depend on the eccentricity of the system, which is poorly constrained due to the high-velocity jitter ( ∼ 80 m s − 1 ). Assuming a circular orbit, the star has a mass of 1 . 16 ± 0 . 04 M and radius of 1 . 22 ± 0 . 02 R , while the planet has a mass of 0 . 860 ± 0 . 164 M J and a radius of 1 . 789 ± 0 . 025 R J . The second planet, HAT-P-33b, orbits the bright V = 11.188 late-F dwarf star GSC 2461-00988, with a period P = 3 . 474474 ± 0 . 000001 d. As for HAT-P-32, the stellar and planetary masses and radii of HAT-P-33 depend on the eccentricity, which is poorly constrained due to the high jitter ( ∼ 50 m s − 1 ). In this case, spectral line bisector spans (BSs) are significantly anti-correlated with the radial velocity residuals, and we are able to use this correlation to reduce the residual rms to ∼ 35 m s − 1 . We find that the star has a mass of 1 . 38 ± 0 . 04 M and a radius of 1 . 64 ± 0 . 03 R while the planet has a mass of 0 . 762 ± 0 . 101 M J and a radius of 1 . 686 ± 0 . 045 R J for an assumed circular orbit. Due to the large BS variations exhibited by both stars we rely on detailed modeling of the photometric light curves to rule out blend scenarios. Both planets are among the largest radii transiting planets discovered to date