175 research outputs found
Titan solar occultation observations reveal transit spectra of a hazy world
High altitude clouds and hazes are integral to understanding exoplanet
observations, and are proposed to explain observed featureless transit spectra.
However, it is difficult to make inferences from these data because of the need
to disentangle effects of gas absorption from haze extinction. Here, we turn to
the quintessential hazy world -- Titan -- to clarify how high altitude hazes
influence transit spectra. We use solar occultation observations of Titan's
atmosphere from the Visual and Infrared Mapping Spectrometer (VIMS) aboard
NASA's Cassini spacecraft to generate transit spectra. Data span 0.88-5 microns
at a resolution of 12-18 nm, with uncertainties typically smaller than 1%. Our
approach exploits symmetry between occultations and transits, producing transit
radius spectra that inherently include the effects of haze multiple scattering,
refraction, and gas absorption. We use a simple model of haze extinction to
explore how Titan's haze affects its transit spectrum. Our spectra show strong
methane absorption features, and weaker features due to other gases. Most
importantly, the data demonstrate that high altitude hazes can severely limit
the atmospheric depths probed by transit spectra, bounding observations to
pressures smaller than 0.1-10 mbar, depending on wavelength. Unlike the usual
assumption made when modeling and interpreting transit observations of
potentially hazy worlds, the slope set by haze in our spectra is not flat, and
creates a variation in transit height whose magnitude is comparable to those
from the strongest gaseous absorption features. These findings have important
consequences for interpreting future exoplanet observations, including those
from NASA's James Webb Space Telescope.Comment: Updated journal reference; data available via
http://sites.google.com/site/tdrobinsonscience/science/tita
Physical inactivity amplifies the negative association between sleep quality and depressive symptoms.
Poor sleep quality and physical inactivity are known risk factors for depressive symptoms. Yet, whether these factors differently contribute to depressive symptoms and whether they interact with one another remains unclear. Here, we examined how sleep quality and physical activity influence depressive symptoms in 79,274 adults 50 years of age or older (52.4% women) from the Survey of Health, Aging and Retirement in Europe (SHARE) study. Sleep quality (poor vs. good), physical activity (inactive vs. active), and depressive symptoms (0 to 12 score) were repeatedly collected (7 waves of data collection) between 2004 and 2017. Results showed that sleep quality and physical activity were associated with depressive symptoms. Specifically, participants with poorer sleep quality reported more depressive symptoms than participants with better sleep quality (b = 1.85, 95% CI = 1.83-1.86, p < .001). Likewise, compared to physically active participants, physically inactive participants reported more depressive symptoms (b = 0.44, 95% CI = 0.42-0.45, p < .001). Moreover, sleep quality and physical activity showed an interactive association with depressive symptoms (b = 0.17, 95% CI = 0.13-0.20, p < .001). The negative association between poor sleep quality and higher depressive symptoms was stronger in physically inactive than active participants. These findings suggest that, in adults 50 years of age or older, both poor sleep quality and physical inactivity are related to an increase in depressive symptoms. Moreover, the detrimental association between poor sleep quality and depressive symptoms is amplified in physically inactive individuals
Titan's atmosphere as observed by Cassini/VIMS solar occultations: CH, CO and evidence for CH absorption
We present an analysis of the VIMS solar occultations dataset, which allows
us to extract vertically resolved information on the characteristics of Titan's
atmosphere between 100-700 km with a characteristic vertical resolution of 10
km. After a series of data treatment procedures, 4 occultations out of 10 are
retained. This sample covers different seasons and latitudes of Titan. The
transmittances show clearly the evolution of the haze and detect the detached
layer at 310 km in Sept. 2011 at mid-northern latitudes. Through the inversion
of the transmission spectra with a line-by-line radiative transfer code we
retrieve the vertical distribution of CH and CO mixing ratio. The two
methane bands at 1.4 and 1.7 {\mu}m are always in good agreement and yield an
average stratospheric abundance of %. This is significantly less
than the value of 1.48% obtained by the GCMS/Huygens instrument. The analysis
of the residual spectra after the inversion shows that there are additional
absorptions which affect a great part of the VIMS wavelength range. We
attribute many of these additional bands to gaseous ethane, whose near-infrared
spectrum is not well modeled yet. Ethane contributes significantly to the
strong absorption between 3.2-3.5 {\mu}m that was previously attributed only to
C-H stretching bands from aerosols. Ethane bands may affect the surface windows
too, especially at 2.7 {\mu}m. Other residual bands are generated by stretching
modes of C-H, C-C and C-N bonds. In addition to the C-H stretch from aliphatic
hydrocarbons at 3.4 {\mu}m, we detect a strong and narrow absorption at 3.28
{\mu}m which we tentatively attribute to the presence of PAHs in the
stratosphere. C-C and C-N stretching bands are possibly present between 4.3-4.5
{\mu}m. Finally, we obtain the CO mixing ratio between 70-170 km. The average
result of ppm is in good agreement with previous studies.Comment: 51 pages, 28 figure
Shock wave lithotripsy for a renal stone in a tetraplegic patient as a trigger for life-threatening posterior reversible encephalopathy syndrome
Shock wave lithotripsy (SWL) is considered a non-invasive treatment for urinary stones and usually advocated for frail patients with spinal cord injury (SCI). We report a life-threatening complication, called posterior reversible encephalopathy syndrome (PRES), in a tetraplegic person who underwent SWL for a small renal stone. Based on our experience, we recommend performing SWL with caution in SCI patients and in tertiary referral hospitals that can promptly manage similar severe complications
Experience of a tertiary referral center in managing bladder cancer in conjunction with neurogenic bladder
Study design: Case series. Objectives: The aim of this study was to present our experience with the management of bladder cancer (BCa) in individuals followed for neurogenic bladder (NB). Setting: An Italian tertiary referral center for NB. Methods: We retrospectively collected all pre-operative, intra-operative, and post-operative data of our NB cases with BCa, diagnosed from 2004 to 2019. Results: We included ten cases: eight with acquired spinal cord injury (SCI) and two with myelomeningocele (MMC). Considering individuals with acquired SCI, the median age at BCa diagnosis and time since SCI were 53 and 34 years, respectively. One out of seven cases had positive urine cytology. All cases underwent a radical cystectomy, diagnosing squamous cell carcinoma (SCC) and transitional cell carcinoma in 60 and 40% cases, respectively. Surgical-related complications occurred after 90% procedures. Three out of eight individuals with acquired SCI died 2, 12, and 80 months after the diagnosis. Both individuals with MMC presented no evidence of disease after 24 and 27 months. Conclusions: BCa in individuals with NB proved to be associated with a diagnosis at an advanced stage and a high rate of surgical complications. In this population we advocate annual genitourinary ultrasound exam and urine cytology, and cystoscopy in all cases of macrohematuria. Considering the low accuracy of urine cytology and the difficult-to-interpret inflamed bladder walls at cystoscopy in NB, a patient-tailored follow-up schedule based on specific risk factors (e.g., smoking status, indwelling urinary catheter) is mandatory to diagnose and treat BCa at an early stage
Cognitive-bias modification intervention to improve physical activity in patients following a rehabilitation programme:protocol for the randomised controlled IMPACT trial
Shift in the larval phenology of a marine ectotherm due to ocean warming with consequences for larval transport
Ejaculation-sparing thulium laser enucleation of the prostate (ES-ThuLEP): outcomes on a large cohort
Purpose: To assess the effects of a new ejaculation-sparing thulium laser enucleation of the prostate (ES-ThuLEP) technique on sexual functions and micturition, in patients with lower urinary tract symptoms secondary to benign prostatic hyperplasia (BPH) and to evaluate how the surgical technique of ES-ThuLEP can lead to ejaculation preservation. Methods: A prospective study was carried out between January 2015 and January 2018 on patients with surgical indication for BPH, who wished to preserve ejaculation. The patients were treated with ES-ThuLEP and were evaluated before and 3 and 6 months after surgery. Three validated questionnaires (ICIQ-MLUTSsex, IIEF-5 and IPSS) were used to assess changes in ejaculation, erectile function and urinary symptoms. Uroflowmetry (Qmax and Qavg), post-void residual volume and voided volume were also evaluated, to assess micturition improvement. Patients with moderate to severe erectile dysfunction were excluded. Statistical analysis was performed with the Student\u2019s t test, Chi-square test and logistic regression analysis. Results: Two hundred and eighty three patients were enrolled. Ejaculation was spared in 203 and 219 patients at 3 and 6 months after surgery. No significant differences were observed between erectile function before and after surgery: baseline IIEF-5 = 16.2 \ub1 4.47 vs 16.7 \ub1 2.9 (p = 0.419) and 17.7 \ub1 3.2 (p = 0.410) at 3 and 6 months. Significant improvement in urinary symptoms was achieved: baseline IPSS = 19.4 \ub1 7.24 vs 5.8 \ub1 4.3 (p = 0.032) and 3.9 \ub1 4.1 (p = 0.029) at 3 and 6 months. Conclusion: ES-ThuLEP effectively preserved ejaculation in over two thirds of the patients without compromising micturition improvement or erectile function. ES-ThuLEP could be a valid treatment option for BPH in young and sexually active men
RHESSI images and spectra of two small flares
We studied the evolution of two small flares (GOES class C2 and C1) that
developed in the same active region with different morphological
characteristics: one is extended and the other is compact. We analyzed the
accuracy and the consistency of different algorithms implemented in RHESSI
software to reconstruct the image of the emitting sources, for energies between
3 and 12 keV. We found that all tested algorithms give consistent results for
the peak position whil the other parameters can differ at most by a factor 2.
Pixon and Forward-fit generally converge to similar results but Pixon is more
reliable for reconstructing a complex source. We investigated the spectral
characteristics of the two flares during their evolution in the 3--25 keV
energy band. We found that a single thermal model of the photon spectrum is
inadequate to fit the observations and we needed to add either a non-thermal
model or a hot thermal one.The non-thermal and the double thermal fits are
comparable. If we assume a non-thermal model, the non-thermal energy is always
higher than the thermal one.Only during the very final decay phase a single
thermal model fits fairly well the observed spectrum.Comment: 26 pages, 11 figures, accepted by Solar Physic
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