ABSTRACT
We present an infrared (IR) characterization of the born-again planetary nebulae (PNe) A 30 and A 78 using IR images and spectra. We demonstrate that the carbon-rich dust in A 30 and A 78 is ...spatially coincident with the H-poor ejecta and coexists with hot X-ray-emitting gas up to distances of 50 arcsec from the central stars of PNe (CSPNe). Dust forms immediately after the born-again event and survives for 1000 yr in the harsh environment around the CSPN as it is destroyed and pushed away by radiation pressure and dragged by hydrodynamical effects. Spitzer IRS spectral maps showed that the broad spectral features at 6.4 and 8.0 μm, attributed to amorphous carbon formed in H-deficient environments, are associated with the disrupted disc around their CSPN, providing an optimal environment for charge exchange reactions with the stellar wind that produces the soft X-ray emission of these sources. Nebular and dust properties are modelled for A 30 with cloudy taking into account different carbonaceous dust species. Our models predict dust temperatures in the 40–230 K range, five times lower than predicted by previous works. Gas and dust masses for the born-again ejecta in A 30 are estimated to be $M_\mathrm{gas}=4.41^{+0.55}_{-0.14}\times 10^{-3}$ M⊙ and $M_\mathrm{dust}=3.20^{+3.21}_{-2.06}\times 10^{-3}$ M⊙, which can be used to estimate a total ejected mass and mass-loss rate for the born-again event of $7.61^{+3.76}_{-2.20}\times 10^{-3}$ M⊙ and $\dot{M}=(5{\!-\!}60)\times 10^{-5}$ M⊙ yr−1, respectively. Taking into account the carbon trapped into dust grains, we estimate that the C/O mass ratio of the H-poor ejecta of A 30 is larger than 1, which favours the very late thermal pulse model over the alternate hypothesis of a nova-like event.
Abstract
Cold dark matter (CDM) has shown to be an excellent candidate for the dark matter (DM) of the Universe at large scales; however, it presents some challenges at the galactic level. The scalar ...field dark matter (SFDM), also called fuzzy, wave, Bose–Einstein condensate, or ultralight axion DM, is identical to CDM at cosmological scales but different at the galactic ones. SFDM forms core haloes, it has a natural cut-off in its matter power spectrum, and it predicts well-formed galaxies at high redshifts. In this work we reproduce the rotation curves of high-resolution low surface brightness (LSB) and SPARC galaxies with two SFDM profiles: (1) the soliton+NFW profile in the fuzzy DM (FDM) model, arising empirically from cosmological simulations of real, non-interacting scalar field (SF) at zero temperature, and (2) the multistate SFDM (mSFDM) profile, an exact solution to the Einstein–Klein–Gordon equations for a real, self-interacting SF, with finite temperature into the SF potential, introducing several quantum states as a realistic model for an SFDM halo. From the fits with the soliton+NFW profile, we obtained for the boson mass 0.212 < mψ/(10−23 eV/c2) < 27.0 and for the core radius 0.326 < rc/kpc < 8.96. From the combined analysis with the LSB galaxies, we obtained mψ = 0.554 × 10−23 eV, a result in tension with the severe cosmological constraints. Also, we show the analytical mSFDM model fits the observations as well as or better than the empirical soliton+NFW profile, and it reproduces naturally the wiggles present in some galaxies, being a theoretically motivated framework additional or alternative to the FDM profile.
Background
In Spring 2020, the COVID‐19 pandemic sent universities into emergency remote education. The pandemic has been disruptive but offers the opportunity to learn about ways to support students ...in other situations where abrupt changes to teaching and learning are necessary.
Purpose/Hypothesis
We described the responses of engineering and computer science students to a series of prompts about their experiences with remote learning.
Design/Method
Data about students' remote learning experiences were collected from undergraduate engineering and computer science students at four different universities through an end‐of‐semester survey. Descriptive statistics were calculated, and qualitative responses were analyzed using qualitative content analysis through the lenses of master narrative theory and sociocultural theory.
Results
Student responses revealed how their individual circumstances combined to reduce motivation, create home environments detrimental to completing schoolwork, and increase stress. Many students described the negative impacts of remote learning, but some students found positive aspects of the situation. The majority of students did not indicate a change in their desire or plans to pursue engineering or computer science majors.
Conclusions
There was wide variation in how students experienced the disruption to university learning during Spring 2020. Implications of this paper can help not only in cases where emergency remote learning is needed in the future but also as universities seek to return to “normal” operations in 2022 and beyond.
In this randomized trial involving patients with acute ischemic stroke with proximal anterior circulation occlusion, endovascular treatment with a Solitaire stent retriever was more effective than ...medical therapy alone in improving functional outcomes at 90 days.
Recently completed prospective, randomized trials involving patients with acute stroke have consistently shown a clinical benefit for mechanical thrombectomy.
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Our study, called the Randomized Trial of Revascularization with Solitaire FR Device versus Best Medical Therapy in the Treatment of Acute Stroke Due to Anterior Circulation Large Vessel Occlusion Presenting within Eight Hours of Symptom Onset (REVASCAT), shares the following four features with the previously cited trials: enrollment limited to patients with imaging-based evidence of proximal occlusion of the M1 segment (main trunk) of the middle cerebral artery with or without concomitant occlusion of the internal carotid artery, imaging-based exclusion . . .
The textbook description of mitochondrial respiratory complexes (RCs) views them as free-moving entities linked by the mobile carriers coenzyme Q (CoQ) and cytochrome c (cyt c). This model (known as ...the fluid model) is challenged by the proposal that all RCs except complex II can associate in supercomplexes (SCs). The proposed SCs are the respirasome (complexes I, III, and IV), complexes I and III, and complexes III and IV. The role of SCs is unclear, and their existence is debated. By genetic modulation of interactions between complexes I and III and III and IV, we show that these associations define dedicated CoQ and cyt c pools and that SC assembly is dynamic and organizes electron flux to optimize the use of available substrates.
Background
Fibromyalgia (FM) is a chronic pain disorder of unknown aetiopathogenesis, in which the role of activity of the hypothalamic–pituitary–adrenal (HPA) axis is not clearly established.
...Methods
This study analysed the modulatory effects of disease chronicity and severity on cortisol levels. Hair cortisol concentrations (HCC) and clinical evaluation data (pain severity, impact of FM on daily activities, depression, anxiety, fatigue and insomnia) were collected from 47 female patients with FM and 36 healthy women (HW).
Results
The results showed that disease chronicity, with a negative effect, and symptom severity, with a positive effect, were independent predictors of HCC. Patients with a shorter disease duration had higher HCC than patients with a longer disease duration and healthy participants. Furthermore, patients with greater symptom severity had higher HCC than those patients with lower clinical severity and healthy participants. While disease chronicity in FM was associated with a decrease in HCC, clinical severity increased HCC.
Conclusions
These results support the existence of a dysfunction in the regulation of the HPA axis in FM and its possible contribution to chronic pain development.
Significance
This is the first study to assess hair cortisol concentrations in a specific sample of patients with fibromyalgia (FM). This method is especially useful for the assessment of long‐term regular cortisol excretion. Results showed a two‐component model for explaining cortisol levels: disease chronicity, with a negative effect, and symptom severity, with a positive effect. This suggests that severe pain/stress evokes higher cortisol levels at earlier stages of FM, while in the longer term a decrease in cortisol levels was observed.
Clinical depression is associated with reductions in white-matter integrity in several long tracts of the brain. The extent to which these findings are localized or related to depressive symptoms or ...personality traits linked to disease risk remains unclear. Method Members of the Lothian Birth Cohort 1936 (LBC936) were assessed in two waves at mean ages of 70 and 73 years. At wave 1, they underwent assessments of depressive symptoms and the personality traits of neuroticism and extraversion. Brain diffusion magnetic resonance imaging (MRI) data were obtained at the second wave and mood assessments were repeated. We tested whether depressive symptoms were related to reduced white-matter tract fractional anisotropy (FA), a measure of integrity, and then examined whether high neuroticism or low extraversion mediated this relationship.
Six hundred and sixty-eight participants provided useable data. Bilateral uncinate fasciculus FA was significantly negatively associated with depressive symptoms at both waves (standardized β=0.12-0.16). Higher neuroticism and lower extraversion were also significantly associated with lower uncinate FA bilaterally (standardized β=0.09-0.15) and significantly mediated the relationship between FA and depressive symptoms.
Trait liability to depression and depressive symptoms are associated with reduced structural connectivity in tracts connecting the prefrontal cortex with the amygdala and anterior temporal cortex. These effects suggest that frontotemporal disconnection is linked to the etiology of depression, in part through personality trait differences.
Immune signatures at birth could be associated with clinical outcomes and will improve our understanding of immunity prenatal programming.
Data come from 235 newborns from the cohort study NELA. ...Production of cytokines was determined using Luminex technology. Associations between cytokine concentrations with sex and season of birth were examined by multivariate regression models.
Umbilical cord blood cells produced high levels of inflammatory cytokines, moderate levels of Th1/Th2/Tr-related cytokines, and low levels of Th17 cytokines. Compared to females, male newborn cells secreted higher levels of Th2 (peptidoglycan-stimulated IL-13, odds ratio OR = 2.26; 95% CI 1.18, 4.31, p value = 0.013) and Th17 (polyinosinic:polycytidylic acid-stimulated IL-23, OR = 1.82, 95% CI 1.01, 3.27, p value = 0.046) and lower levels of Th1 (olive-stimulated IL-2, OR = 0.56, 95% CI 0.31, 0.99, p value = 0.047) cytokines. Also, children born during warm seasons showed decreased innate cytokine response to peptidoglycan (IL-6, OR = 0.28, 95% CI 0.15, 0.52, p value < 0.001) compared to those born in cold seasons; meanwhile, adaptive immunity cytokines were more frequently secreted by children born during warm seasons in response to allergen extracts (IL-10, OR = 2.11, 95% CI 1.12, 3.96, p value = 0.020; IL-17F, OR = 3.31, 95% CI 1.83, 5.99, p value < 0.001).
Newborns showed specific cytokines signatures influenced by sex and season of birth.
There is a limited number of population-based studies on the immune status at birth and the influence of prenatal and perinatal factors on it. Characterization of cytokine signatures at birth related to the prenatal environment could improve our understanding of immunity prenatal programming. Newborns exhibit specific unstimulated and stimulated cytokine signatures influenced by sex and season of birth. Unstimulated and stimulated cytokine signatures in newborns may be associated with the development of related clinical outcomes later in life.
The aim of this work was to investigate chitosomes, i.e. liposomes coated by a polyelectrolyte complex between chitosan (CH) and xantan gum (XG), as potential delivery system for oral administration ...of the protein C-phycocyanin. To this purpose several CH–XG-microcomplexes were prepared in aqueous lactic acid at different chitosan–xanthan gum percent ratios and rheological properties of the microcomplexes were studied to analyse the contribution of chitosan and xanthan gum in the reaction of microcomplexation. After establishing the best microcomplexes, chitosomes were prepared by coating C-phycocyanin loaded liposomes with the CH–XG hydrogels using spray-drying or freeze-drying. The chitosomes were characterized in terms of morphology, size distribution, zeta potential, swelling properties, drug release, and mucoadhesive properties. Rheological studies showed the influence of xanthan gum in the microcomplex properties. Moreover, obtained results demonstrated the effects of formulation and process variables on particle size, drug content, swelling, drug release, and especially on the mucoadhesiveness of C-PC chitosomes of CH–XG. In particular, chitosomes prepared by spray-drying technique using CH–XG in 0.5/8.0 (w/w) ratio showed a regular surface and a drug release characteristic for a Fickian diffusion of the active ingredient. The in vitro mucoadhesive study revealed that the spray-drying method is advantageous to prepare C-phycocyanin loaded chitosomes with excellent mucoadhesive properties for colonic drug delivery.
The global upper ocean has been warming during the last decades accompanied with a chlorophyll‐a (Chl‐a) and productivity decrease. Whereas subtropical gyres show similar trends, Eastern Boundary ...Upwelling Systems are thought to increase in productivity due to increased trade winds. This study analyzes recent trends in sea surface temperature (SST), Chl‐a, net primary production (NPP) and meridional wind stress in the Eastern North Atlantic subtropical gyre (NASE) in order to examine if the global trends can be detected in open ocean and upwelling areas and how the ocean biota responds. Satellite data of such variables of the last 15–40 years were analyzed to calculate mean trends in upwelling areas in the Canary upwelling system and open ocean areas around the Azores, Madeira and the Canary Islands. Our results show significant warming in the area with a maximum of 2.7°C per century for the Azores. Moreover, a general decreasing trend for Chl‐a and NPP seems to be more evident in the permanent upwelling areas, which will be responsible for a loss of 0.13% of the global NPP per century. Our results also highlight a significant expansion of the oceanic desert area of 10% with an increase in unproductive days of up to 84 days in the last 20 years. The competitive relationship of stratification and wind stress in the Canary upwelling system might be a more plausible explanation for the decrease in Chl‐a and NPP in upwelling areas linked to the increase in upwelling favorable wind stress and the surface warming.
Plain Language Summary
The increase in global sea surface temperature (SST) is accompanied with a decrease in chlorophyll‐a (Chl‐a) and primary productivity. Microscopic algae called phytoplankton and their pigment Chl‐a are responsible both for the production of organic material made available for larger animals as food source and the production of oxygen. Different oceanic areas such as the open ocean or coastal so‐called upwelling areas in the Eastern North Atlantic Subtropical show characteristic production regimes linked to ocean temperature or wind stress. The main goal of this study was to analyze trends based on satellite data of SST, Chl‐a, productivity and wind stress in different oceanic areas in order to identify the biological response to the physical forcing. Our study shows that the highly productive upwelling area along Northwest Africa and Western Iberia is warming at a slower pace than open ocean areas around Madeira, the Canary Islands and the Azores where a maximum increase of 2.7°C per century was found. Similarly, the Chl‐a and the productivity is decreasing faster in the same coastal areas and slower in open ocean areas. If the rate continues it will be responsible for a global loss of 0.13% of the global productivity per century.
Key Points
Higher warming rates in open ocean areas than in upwelling areas and general wind stress increases in upwelling areas
Expansion of desert areas in the open ocean and a general chlorophyll‐a (Chl‐a) and productivity decrease, with more pronounced trends in upwelling areas
The competitive relationship of wind stress and stratification might be responsible for Chl‐a and productivity trends in upwelling areas
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