HAZMAT VI: The Evolution of Extreme Ultraviolet Radiation Emitted from Early M Star

Quantifying the evolution of stellar extreme ultraviolet (EUV, 100 -- 1000 $\overset{\circ}{A}$) emission is critical for assessing the evolution of planetary atmospheres and the habitability of M dwarf systems. Previous studies from the HAbitable Zones and M dwarf Activity across Time (HAZMAT) program showed the far- and near-UV (FUV, NUV) emission from M stars at various stages of a stellar lifetime through photometric measurements from the Galaxy Evolution Explorer (GALEX). The results revealed increased levels of short-wavelength emission that remain elevated for hundreds of millions of years. The trend for EUV flux as a function of age could not be determined empirically because absorption by the interstellar medium prevents access to the EUV wavelengths for the vast majority of stars. In this paper, we model the evolution of EUV flux from early M stars to address this observational gap. We present synthetic spectra spanning EUV to infrared wavelengths of 0.4 $\pm$ 0.05 M$_{\odot}$ stars at five distinct ages between 10 and 5000 Myr, computed with the PHOENIX atmosphere code and guided by the GALEX photometry. We model a range of EUV fluxes spanning two orders of magnitude, consistent with the observed spread in X-ray, FUV, and NUV flux at each epoch. Our results show that the stellar EUV emission from young M stars is 100 times stronger than field age M stars, and decreases as t$^{-1}$ after remaining constant for a few hundred million years. This decline stems from changes in the chromospheric temperature structure, which steadily shifts outward with time. Our models reconstruct the full spectrally and temporally resolved history of an M star's UV radiation, including the unobservable EUV radiation, which drives planetary atmospheric escape, directly impacting a planet's potential for habitability.Comment: 23 pages, 15 figures, accepted to Ap

Rate of complications due to carotid angioplasty in a tertiary university hospital

Introduction: Stenoses greater than 50% in the cervical internal carotid artery cause up to 8% of all ischemic strokes. Carotid artery stenting (CAS) is an effective alternative to prevent cerebrovascular events to occur. According to recommendations from the American Heart Association/American Stroke Association, CAS is indicated for symptomatic patients with internal carotid stenosis greater than 70% (measured by non-invasive methods), as long as the risk for periprocedural stroke or death is less than 6%. There is few information about complication rates of CAS in developing countries. Objectives: The primary goal of this study was to evaluate the frequency of any stroke or death until hospital discharge after CAS in symptomatic patients with carotid stenosis in a tertiary university hospital. Other complication rates were also assessed as secondary aims. Methods: A single-center retrospective study based on the analysis of charts from patients submitted to CAS between April 2011 and March 2016. Inclusion criteria were: age ≥ 18 years old, admission and follow-up by neurologists from the Neurology Ward, performance of CAS according to the hospital´s protocol (carotid stenosis ≥70%, patients with transient ischemic attack (TIA), amaurosis fugax or minor stroke in the last 180 days, and life expectancy greater than a year). Patients not followed by neurologists after CAS were excluded. Results: A total of 65 patients were included: 3 (4.6%) suffered stroke or death after CAS. Two of these patients presented ischemic strokes and one, an hemorrhagic stroke that lead to death. Myocardial infarctions were not identified, as well as carotid ruptures or dissections, hyperperfusion syndrome, artery perforations, stent thrombosis or encephalopathy. Minor complication rates were: 12.3% for hypotension, 9.2% for bradycardia, 1.5% for TIA, 3.1% for carotid vasospasm and 6.2% for acute kidney injury. The total rate of minor complications was 23.1%, and none of then led to permanent harm. Conclusions: The rate of stroke or death in a reference tertiary service in a developing country was in line with international recommendations

Oxytocin Normalizes Approach-Avoidance Behavior in Women With Borderline Personality Disorder

Background: Interpersonal deficits are a core symptom of borderline personality disorder (BPD), which could be related to increased social threat sensitivity and a tendency to approach rather than avoid interpersonal threats. The neuropeptide oxytocin has been shown to reduce threat sensitivity in patients with BPD and to modify approach–avoidance behavior in healthy volunteers. Methods: In a randomized, double-blind placebo-controlled between-subject design, 53 unmedicated women with BPD and 61 healthy women participated in an approach–avoidance task 75 min after intranasal substance administration (24 IU of oxytocin or placebo). The task assesses automatic approach–avoidance tendencies in reaction to facial expressions of happiness and anger. Results: While healthy participants responded faster to happy than angry faces, the opposite response pattern, that is, faster reactions to angry than happy faces, was found in patients with BPD. In the oxytocin condition, the “congruency effect” (i.e., faster avoidance of facial anger and approach of facial happiness vice versa) was increased in both groups. Notably, patients with BPD exhibited a congruency effect toward angry faces in the oxytocin but not in the placebo condition. Conclusions: This is the second report of deficient fast, automatic avoidance responses in terms of approach behavior toward interpersonal threat cues in patients with BPD. Intranasally administered oxytocin was found to strengthen avoidance behavior to social threat cues and, thus, to normalize fast action tendencies in BPD. Together with the previously reported oxytocinergic reduction of social threat hypersensitivity, these results suggest beneficial effects of oxytocin on interpersonal dysfunctioning in BPD

Magnons at low excitations: Observation of incoherent coupling to a bath of two-level-systems

Collective magnetic excitation modes, magnons, can be coherently coupled to microwave photons in the single excitation limit. This allows for access to quantum properties of magnons and opens up a range of applications in quantum information processing, with the intrinsic magnon linewidth representing the coherence time of a quantum resonator. Our measurement system consists of a yttrium iron garnet (YIG) sphere and a three-dimensional (3D) microwave cavity at temperatures and excitation powers typical for superconducting quantum circuit experiments. We perform spectroscopic measurements to determine the limiting factor of magnon coherence at these experimental conditions. Using the input-output formalism, we extract the magnon linewidth $\kappa_\mathrm{m}$. We attribute the limitations of the coherence time at lowest temperatures and excitation powers to incoherent losses into a bath of near-resonance two-level systems (TLSs), a generic loss mechanism known from superconducting circuits under these experimental conditions. We find that the TLSs saturate when increasing the excitation power from quantum excitation to multi-photon excitation and their contribution to the linewidth vanishes. At higher temperatures, the TLSs saturate thermally and the magnon linewidth decreases as well

Introducing coherent time control to cavity magnon-polariton modes

By connecting light to magnetism, cavity magnon-polaritons (CMPs) can link quantum computation to spintronics. Consequently, CMP-based information processing devices have emerged over the last years, but have almost exclusively been investigated with single-tone spectroscopy. However, universal computing applications will require a dynamic and on-demand control of the CMP within nanoseconds. Here, we perform fast manipulations of the different CMP modes with independent but coherent pulses to the cavity and magnon system. We change the state of the CMP from the energy exchanging beat mode to its normal modes and further demonstrate two fundamental examples of coherent manipulation. We first evidence dynamic control over the appearance of magnon-Rabi oscillations, i.e., energy exchange, and second, energy extraction by applying an anti-phase drive to the magnon. Our results show a promising approach to control building blocks valuable for a quantum internet and pave the way for future magnon-based quantum computing research

Rate of complications due to carotid angioplasty in a tertiary university hospital

Introduction: Stenoses greater than 50% in the cervical internal carotid artery cause up to 8% of all ischemic strokes. Carotid artery stenting (CAS) is an effective alternative to prevent cerebrovascular events to occur. According to recommendations from the American Heart Association/American Stroke Association, CAS is indicated for symptomatic patients with internal carotid stenosis greater than 70% (measured by non-invasive methods), as long as the risk for periprocedural stroke or death is less than 6%. There is few information about complication rates of CAS in developing countries. Objectives: The primary goal of this study was to evaluate the frequency of any stroke or death until hospital discharge after CAS in symptomatic patients with carotid stenosis in a tertiary university hospital. Other complication rates were also assessed as secondary aims. Methods: A single-center retrospective study based on the analysis of charts from patients submitted to CAS between April 2011 and March 2016. Inclusion criteria were: age ≥ 18 years old, admission and follow-up by neurologists from the Neurology Ward, performance of CAS according to the hospital´s protocol (carotid stenosis ≥70%, patients with transient ischemic attack (TIA), amaurosis fugax or minor stroke in the last 180 days, and life expectancy greater than a year). Patients not followed by neurologists after CAS were excluded. Results: A total of 65 patients were included: 3 (4.6%) suffered stroke or death after CAS. Two of these patients presented ischemic strokes and one, an hemorrhagic stroke that lead to death. Myocardial infarctions were not identified, as well as carotid ruptures or dissections, hyperperfusion syndrome, artery perforations, stent thrombosis or encephalopathy. Minor complication rates were: 12.3% for hypotension, 9.2% for bradycardia, 1.5% for TIA, 3.1% for carotid vasospasm and 6.2% for acute kidney injury. The total rate of minor complications was 23.1%, and none of then led to permanent harm. Conclusions: The rate of stroke or death in a reference tertiary service in a developing country was in line with international recommendations

Current Population Statistics Do Not Favor Photoevaporation over Core-Powered Mass Loss as the Dominant Cause of the Exoplanet Radius Gap

We search for evidence of the cause of the exoplanet radius gap, i.e. the dearth of planets with radii near $1.8\ R_\oplus$. If the cause was photoevaporation, the radius gap should trend with proxies for the early-life high-energy emission of planet-hosting stars. If, alternatively, the cause was core-powered mass loss, no such trends should exist. Critically, spurious trends between the radius gap and stellar properties arise from an underlying correlation with instellation. After accounting for this underlying correlation, we find no trends remain between the radius gap and stellar mass or present-day stellar activity as measured by near-UV emission. We dismiss the nondetection of a radius gap trend with near-UV emission because present-day near-UV emission is unlikely to trace early-life high-energy emission, but we provide a catalog of GALEX near-UV and far-UV emission measurements for general use. We interpret the nondetection of a radius gap trend with stellar mass by simulating photoevaporation with mass-dependent evolution of stellar high-energy emission. The simulation produces an undetectable trend between the radius gap and stellar mass under realistic sources of error. We conclude that no evidence, from this analysis or others in the literature, currently exists that clearly favors either photoevaporation or core powered mass loss as the primary cause of the exoplanet radius gap. However, repeating this analysis once the body of well-characterized $< 4\ R_\oplus$ planets has roughly doubled could confirm or rule out photoevaporation.Comment: 27 pages, 32 figures, accepted to Ap

Exogenous LRRK2G2019S induces parkinsonian-like pathology in a nonhuman primate

Parkinson’s disease (PD) is the second most prevalent neurodegenerative disease among the elderly. To understand pathogenesis and to test therapies, animal models that faithfully reproduce key pathological PD hallmarks are needed. As a prelude to developing a model of PD, we tested the tropism, efficacy, biodistribution, and transcriptional impact of canine adenovirus type 2 (CAV-2) vectors in the brain of Microcebus murinus, a nonhuman primate that naturally develops neurodegenerative lesions. We show that introducing helper-dependent (HD) CAV-2 vectors results in long-term, neuron-specific expression at the injection site and in afferent nuclei. Although HD CAV-2 vector injection induced a modest transcriptional response, no significant adaptive immune response was generated. We then generated and tested HD CAV-2 vectors expressing LRRK2 (leucine-rich repeat kinase 2) and LRRK2 carrying a G2019S mutation (LRRK2G2019S), which is linked to sporadic and familial autosomal dominant forms of PD. We show that HD-LRRK2G2019S expression induced parkinsonian-like motor symptoms and histological features in less than 4 months

The Presence of Human Immunodeficiency Virus-Associated Neurocognitive Disorders Is Associated With a Lower Adherence to Combined Antiretroviral Treatment.

Human immunodeficiency virus (HIV)-associated neurocognitive disorders (HAND) are defined according to their diagnostic degrees as follows: asymptomatic neurocognitive impairment, mild neurocognitive disorder, and HIV-associated dementia. Because high adherence to combined antiretroviral therapy (cART) is required to maintain viral suppression among HIV-infected patients, it is important to investigate the impact of HAND on medication adherence. Our study hypothesis was that patients with HAND had a lower medication adherence than patients who did not have HAND. This was an observational, exploratory, 2-center pilot study of patients who had a state-of-the-art neurocognitive assessment performed between January 2011 and June 2015 while also being followed at their respective adherence clinics. Adherence was measured with electronic monitors. Patients' sociodemographic characteristics, HIV viral load, and CD4 counts were retrieved from the Swiss HIV Cohort Study database. At each time t, adherence was computed as the proportion of patients taking medication as prescribed at that time. We included 59 patients, with a median (Q1, Q3) age of 53 years (47-58) and 39 (66%) were male participants. Twenty-two patients (35%) had no neurocognitive deficits, 16 (27%) patients had HAND, and 21 (35%) patients had non-HAND (mostly depression). Implementation over 3 years showed a significant decline (50%) in medication adherence among patients diagnosed with HAND in comparison with patients who had a normal neuropsychological status or a non-HIV-related cognitive deficit (implementation stayed 90% during follow-up). Our findings support the hypothesis that HAND is associated with reduced cART adherence