Pronounced temporal and spatial variation in the availability of food resources can produce energetic deficits in organisms. Fruit-dependent Bornean orangutans face extreme variation in fruit ...availability and experience negative energy and protein balance during episodes of fruit scarcity. We evaluate the possibility that orangutans of different sexes and ages catabolize muscle tissue when the availability of fruit is low. We assess variation in muscle mass by examining the relationship between urinary creatinine and specific gravity and use the residuals as a non-invasive measure of estimated lean body mass (ELBM). Despite orangutans having a suite of adaptations to buffer them from fruit scarcity and associated caloric deficits, ELBM was lower during low fruit periods in all age-sex classes. As predicted, adult male orangutans had higher ELBM than adult females and immatures. Contrary to expectation, flanged and unflanged males did not differ significantly in ELBM. These findings highlight the precarity of orangutan health in the face of rapid environmental change and add to a growing body of evidence that orangutans are characterized by unique metabolic traits shaped by their unpredictable forest environment.
We report on the discovery of correlations between dust and CO gas tracers of the 0.1–10 au region in planet-forming disks around young intermediate-mass stars. The abundance of refractory elements ...on stellar photospheres decreases as the location of hot CO gas emission recedes to larger disk radii, and as the near-infrared excess emission from hot dust in the inner disk decreases. The linked behavior between these observables demonstrates that the recession of infrared CO emission to larger disk radii traces an inner disk region where dust is being depleted. We also find that Herbig disk cavities have either low (~5–10%) or high (~20–35%) near-infrared excess, a dichotomy that has not been captured by the classic definition of “pre-transitional” disks.
Abstract
We present 2007–2020 SpeX VISNIR spectral monitoring of the highly variable RW Aur A CTTS. We find direct evidence for a highly excited, IR-bright, asymmetric, and time-variable system. ...Comparison of the spectral and temporal trends found determines five different components: (1) a stable continuum from 0.7 to 1.3
μ
m, with color temperature ∼4000 K, produced by the CTTS photospheric surface; (2) variable hydrogen emission lines emitted from hot excited hydrogen in the CTTS’s protostellar atmosphere/accretion envelope; (3) hot CO gas in the CTTS’s protostellar atmosphere/accretion envelope; (4) highly variable 1.8–5.0
μ
m thermal continuum emission with color temperature ranging from 1130 to 1650 K, due to a surrounding accretion disk that is spatially variable and has an inner wall at
r
∼ 0.04 au and
T
∼ 1650 K and outer edges at ∼1200 K; and (5) transient, bifurcated signatures of abundant Fe
ii
+ associated S
i
, Si
i
, and Sr
i
in the system’s jet structures. The bifurcated signatures first appeared in 2015, but these collapsed and disappeared into a small single-peaked protostellar atmosphere feature by late 2020. The temporal evolution of RW Aur A’s spectral signatures is consistent with a dynamically excited CTTS system forming differentiated Vesta-sized planetesimals in an asymmetric accretion disk and migrating them inward to be destructively accreted. By contrast, nearby coeval binary companion RW Aur B evinces only a stable WTTS photospheric continuum from 0.7 to 1.3
μ
m + cold CO gas in absorption + stable 1.8–5.0
μ
m thermal disk continuum emission with color temperature ∼1650 K.
HD 142527 is a young pre-main-sequence star with properties indicative of the presence of a giant planet and/or a low-mass stellar companion. We have analyzed an X-Shooter/Very Large Telescope ...spectrum to provide accurate stellar parameters and accretion rate. This stellar age provides further constraints to the mass of the possible companion estimated by Biller et al., being between 0.20 and 0.35 M sub(middot in circle). Stellar accretion rates obtained from UV Balmer excess modeling and optical photospheric line veiling, and from the correlations with several emission lines spanning from the UV to the near-IR, are consistent with each other. This suggests that almost all gas transferred between both components of the disk is not trapped by the possible planet(s) in between but fall onto the central star, although it is discussed how the gap flow rate could be larger than previously suggested.
We observed a sample of 20 representative Herbig Ae/Be stars and 5 A-type debris discs with PACS onboard Herschel, as part of the GAS in Protoplanetary Systems (GASPS) project. The observations were ...done in spectroscopic mode, and cover the far-infrared lines of O i, C ii, CO, CH+, H2O, and OH. We have a O i 63 μm detection rate of 100% for the Herbig Ae/Be and 0% for the debris discs. The O i 145 μm line is only detected in 25% and CO J = 18-17 in 45% (and fewer cases for higher J transitions) of the Herbig Ae/Be stars, while for C ii 157 μm, we often find spatially variable background contamination. We show the first detection of water in a Herbig Ae disc, HD 163296, which has a settled disc. Hydroxyl is detected as well in this disc. First seen in HD 100546, CH+ emission is now detected for the second time in a Herbig Ae star, HD 97048. We report fluxes for each line and use the observations as line diagnostics of the gas properties. Furthermore, we look for correlations between the strength of the emission lines and either the stellar or disc parameters, such as stellar luminosity, ultraviolet and X-ray flux, accretion rate, polycyclic aromatic hydrocarbon (PAH) band strength, and flaring. We find that the stellar ultraviolet flux is the dominant excitation mechanism of O i 63 μm, with the highest line fluxes being found in objects with a large amount of flaring and among the largest PAH strengths. Neither the amount of accretion nor the X-ray luminosity has an influence on the line strength. We find correlations between the line flux of O i 63 μm and O i 145 μm, CO J = 18-17 and O i 6300 Å, and between the continuum flux at 63 μm and at 1.3 mm, while we find weak correlations between the line flux of O i 63 μm and the PAH luminosity, the line flux of CO J = 3-2, the continuum flux at 63 μm, the stellar effective temperature, and the Brγ luminosity. Finally, we use a combination of theO i 63 μm and 12CO J = 2-1 line fluxes to obtain order of magnitude estimates of the disc gas masses, in agreement with the values that we find from detailed modelling of two Herbig Ae/Be stars, HD 163296 and HD 169142. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.
This work presents X-Shooter/Very Large Telescope spectra of the prototypical, isolated Herbig Ae stars HD 31648 (MWC 480) and HD 163296 over five epochs separated by timescales ranging from days to ...months. Each spectrum spans over a wide wavelength range covering from 310 to 2475 nm. We have monitored the continuum excess in the Balmer region of the spectra and the luminosity of 12 ultraviolet, optical, and near-infrared spectral lines that are commonly used as accretion tracers for T Tauri stars. The observed strengths of the Balmer excesses have been reproduced from a magnetospheric accretion shock model, providing a mean mass accretion rate of 1.11 x 10 super(-7) and 4.50 x 10 super(-7) M sub(middot in circle) yr super(-1) for HD 31648 and HD 163296, respectively. Accretion rate variations are observed, being more pronounced for HD 31648 (up to 0.5 dex). However, from the comparison with previous results it is found that the accretion rate of HD 163296 has increased by more than 1 dex, on a timescale of ~15 yr. Averaged accretion luminosities derived from the Balmer excess are consistent with the ones inferred from the empirical calibrations with the emission line luminosities, indicating that those can be extrapolated to HAe stars. In spite of that, the accretion rate variations do not generally coincide with those estimated from the line luminosities, suggesting that the empirical calibrations are not useful to accurately quantify accretion rate variability.
Abstract Objective The objective of this study was to use motor unit coupling in the time and frequency domains to obtain evidence of changes in motoneuronal drive during walking in subjects with ...stroke. Methods Paired tibialis anterior (TA) EMG activity was sampled during the swing phase of treadmill walking in eight subjects with unilateral stroke. Results On the unaffected side, short-term synchronization was evident from the presence of a narrow central peak in cumulant densities and from the presence of significant coherence between these signals in the 10–25 Hz band. Such indicators of short-term synchrony were either absent or very small on the affected side. Instead, pronounced 10 Hz coupling was observed. Conclusions It is suggested that reduced corticospinal drive to the spinal motoneurones is responsible for the reduced short-term synchrony and coherence in the 10–25 Hz frequency band on the affected side in hemiplegic patients during walking. Significance This is of importance for understanding the mechanisms responsible for reduced gait ability and development of new strategies for gait restoration.
ABSTRACT We have imaged GM Aurigae with the Hubble Space Telescope, detected its disk in scattered light at 1400 and 1650 Å, and compared these with observations at 3300 Å, 5550 Å, 1.1 m, and 1.6 m. ...The scattered light increases at shorter wavelengths. The radial surface brightness profile at 3300 Å shows no evidence of the 24 au radius cavity that has been previously observed in submillimeter observations. Comparison with dust grain opacity models indicates that the surface of the entire disk is populated with submicron grains. We have compiled a spectral energy distribution from 0.1 m to 1 mm and used it to constrain a model of the star + disk system that includes the submillimeter cavity using the Monte Carlo radiative transfer code by Barbara Whitney. The best-fit model image indicates that the cavity should be detectable in the F330W bandpass if the cavity has been cleared of both large and small dust grains, but we do not detect it. The lack of an observed cavity can be explained by the presence of submicron grains interior to the submillimeter cavity wall. We suggest one explanation for this that could be due to a planet of mass <9 MJ interior to 24 au. A unique cylindrical structure is detected in the far-UV data from the Advanced Camera for Surveys/Solar Blind Channel. It is aligned along the system semiminor axis, but does not resemble an accretion-driven jet. The structure is limb brightened and extends 190 35 au above the disk midplane. The inner radius of the limb brightening is 40 10 au, just beyond the submillimeter cavity wall.
Context. Constraining the gas and dust disk structure of transition disks, particularly in the inner dust cavity, is a crucial step toward understanding the link between them and planet formation. HD ...135344B is an accreting (pre-)transition disk that displays the CO 4.7 μm emission extending tens of AU inside its 30 AU dust cavity. Aims. We constrain HD 135344B’s disk structure from multi-instrument gas and dust observations. Methods. We used the dust radiative transfer code MCFOST and the thermochemical code ProDiMo to derive the disk structure from the simultaneous modeling of the spectral energy distribution (SED), VLT/CRIRES CO P(10) 4.75 μm, Herschel/PACS O i 63 μm, Spitzer/IRS, and JCMT 12CO J = 3−2 spectra, VLTI/PIONIER H-band visibilities, and constraints from (sub-)mm continuum interferometry and near-IR imaging. Results. We found a disk model able to describe the current gas and dust observations simultaneously. This disk has the following structure. (1) To simultaneously reproduce the SED, the near-IR interferometry data, and the CO ro-vibrational emission, refractory grains (we suggest carbon) are present inside the silicate sublimation radius (0.08 <R< 0.2 AU). (2) The dust cavity (R< 30 AU) is filled with gas, the surface density of the gas inside the cavity must increase with radius to fit the CO ro-vibrational line profile, a small gap of a few AU in the gas distribution is compatible with current data, and a large gap of tens of AU in the gas does not appear likely. (4) The gas-to-dust ratio inside the cavity is >100 to account for the 870 μm continuum upper limit and the CO P(10) line flux. (5) The gas-to-dust ratio in the outer disk (30 <R< 200 AU) is <10 to simultaneously describe the O i 63 μm line flux and the CO P(10) line profile. (6) In the outer disk, most of the gas and dust mass should be located in the midplane, and a significant fraction of the dust should be in large grains. Conclusions. Simultaneous modeling of the gas and dust is required to break the model degeneracies and constrain the disk structure. An increasing gas surface density with radius in the inner cavity echoes the effect of a migrating jovian planet in the disk structure. The low gas mass (a few Jupiter masses) throughout the HD 135344B disk supports the idea that it is an evolved disk that has already lost a large portion of its mass.
Objective
To evaluate long‐term outcomes of adjunctive therapy with SPN‐804 (Oxtellar XR®, Supernus Pharmaceuticals), an extended‐release tablet formulation of oxcarbazepine (OXC), in adults with ...refractory partial‐onset seizures.
Methods
After completing a 16‐week double‐blind, placebo‐controlled trial of SPN‐804 at fixed dosages (1200 or 2400 mg QD), patients entering this open‐label extension study were converted in blinded fashion to 1200 mg QD SPN‐804 as a target starting dose for long‐term treatment. Patients were followed for 1 year, during which SPN‐804 dosages could be adjusted up to 2400 mg/day according to clinical response.
Results
Of 214 patients, 84% completed 1‐year open‐label treatment. Median maintenance SPN‐804 dosage was 1200 mg; <10% of patients required 2400 mg. Median 28‐day seizure frequency reduction from baseline was 59%; seizure frequency was reduced ≥50% in 58% of patients; 11% were seizure free ≥6 months; and 5% were seizure free ≥1 year. SPN‐804 was discontinued due to adverse events in 5% (n = 10). Incidences of each of the most common adverse events (dizziness, headache, diplopia, nausea, vomiting, balance disorder, blurred vision) were ≤15% during 1‐year follow‐up and occurred most frequently in patients previously naïve to SPN‐804. No new safety signals, no clinically significant changes in health status, and no deaths attributable to SPN‐804 were observed.
Conclusion
SPN‐804 administered once daily for 1 year was effective as adjunctive therapy in improving seizure control and maintaining therapeutic response in adults with refractory partial‐onset seizures. With dosage flexibility, SPN‐804 was well tolerated.
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