Curved broad-band spectral distributions of non-thermal sources like blazars are described well by a log-parabolic law where the second degree term measures the curvature. Log-parabolic energy ...spectra can be obtained for relativistic electrons by means of a statistical acceleration mechanism whose probability of acceleration depends on energy. In this paper we compute the spectra radiated by an electron population via synchrotron and Synchro-Self Compton processes to derive the relations between the log-parabolic parameters. These spectra were obtained by means of an accurate numerical code that takes the proper spectral distributions for single particle emission into account. We found that the ratio between the curvature parameters of the synchrotron spectrum to that of the electrons is equal to 60.2 instead of 0.25, the value foreseen in the d-approximation. Inverse Compton spectra are also intrinsically curved and can be approximated by a log-parabola only in limited ranges. The curvature parameter, estimated around the SED peak, may vary from a lower value than that of the synchrotron spectrum up to that of emitting electrons depending on whether the scattering is in the Thomson or in the Klein-Nishina regime. We applied this analysis to computing the synchro-self Compton emission from the BL Lac object Mkn 501 during the large flare of April 1997. We fit simultaneous BeppoSAX and CAT data and reproduced intensities and spectral curvatures of both components with good accuracy. The large curvature observed in the TeV range was found to be mainly intrinsic, and therefore did not require a large pair production absorption against the extragalactic background. We regard this finding as an indication that the Universe is more transparent at these energies than previously assumed by several models found in the literature. This conclusion is supported by recent detection of two relatively high redshift blazars with HESS.
The Advanced Laser Interferometer Gravitational-Wave Observatory (ALIGO) observatory recently reported the first direct detection of gravitational waves (GW) which triggered ALIGO on 2015 September ...14. We report on observations taken with the Swift satellite two days after the trigger. No new X-ray, optical, UV or hard X-ray sources were detected in our observations, which were focused on nearby galaxies in the GW error region and covered 4.7 deg2 (∼2 per cent of the probability in the rapidly available GW error region; 0.3 per cent of the probability from the final GW error region, which was produced several months after the trigger). We describe the rapid Swift response and automated analysis of the X-ray telescope and UV/Optical telescope data, and note the importance to electromagnetic follow-up of early notification of the progenitor details inferred from GW analysis.
Aims. Open Universe for Blazars is a set of high-transparency multi-frequency data products for blazar science, and the tools designed to generate them. Blazars are drawing growing interest following ...the consolidation of their position as the most abundant type of source in the extragalactic very high-energy γ-ray sky, and because of their status as prime candidate sources in the nascent field of multi-messenger astrophysics. As such, blazar astrophysics is becoming increasingly data driven, depending on the integration and combined analysis of large quantities of data from the entire span of observational astrophysics techniques. The project was therefore chosen as one of the pilot activities within the United Nations Open Universe Initiative, whose objective is to stimulate a large increase in the accessibility and ease of utilisation of space science data for the worldwide benefit of scientific research, education, capacity building, and citizen science. Methods. Our aim is to deliver innovative data science tools for multi-messenger astrophysics. In this work we report on a data analysis pipeline called Swift-DeepSky based on the Swift XRTDAS software and the XIMAGE package, encapsulated into a Docker container. Swift-DeepSky downloads and reads low-level data, generates higher level products, detects X-ray sources, and estimates several intensity and spectral parameters for each detection, thus facilitating the generation of complete and up-to-date science-ready catalogues from an entire space-mission data set. Results. As a first application of our innovative approach, we present the results of a detailed X-ray image analysis based on Swift-DeepSky that was run on all Swift-XRT observations including a known blazar, carried out during the first 14 years of operations of the Neil Gehrels Swift Observatory. Short exposures executed within one week of each other have been added to increase sensitivity, which ranges between ∼1 × 10−12 and ∼1 × 10−14 erg cm−2 s−1 (0.3–10.0 keV). After cleaning for problematic fields, the resulting database includes over 27 000 images integrated in different X-ray bands, and a catalogue, called 1OUSXB, that provides intensity and spectral information for 33 396 X-ray sources, 8896 of which are single or multiple detections of 2308 distinct blazars. All the results can be accessed online in a variety of ways, from the Open Universe portal through Virtual Observatory services, via the VOU-Blazar tool and the SSDC SED builder. One of the most innovative aspects of this work is that the results can be easily reproduced and extended by anyone using the Docker version of the Swift-DeepSky pipeline, which runs on Linux, Mac, and Windows machines, and does not require any specific experience in X-ray data analysis.
Aims. We present a new measurement of the cosmic X-ray background (CXRB) in the 1.5-7 keV energy band, performed by exploiting the Swift X-ray telescope (XRT) data archive. We also present a ...CXRB spectral model in a wider energy band (1.5-200 keV), obtained by combining these data with the recently published Swift-BAT measurement. Methods. From the XRT archive we collect a complete sample of 126 high Galactic latitude gamma-ray burst (GRB) follow-up observations. This provides a total exposure of 7.5 Ms and a sky-coverage of ~7 square degrees which represents a serendipitous survey, well suited for a direct measurement of the CXRB in the 1.5-10 keV interval. Our work is based on a complete characterization of the instrumental background and an accurate measurement of the stray-light contamination and vignetting calibration. Results. We find that the CXRB spectrum in the 1.5-7 keV energy band can be equally well fitted by a single power-law with photon index $\Gamma=1.47\pm0.07$ or a single power-law with photon index $\Gamma=1.41\pm0.06$ and an exponential roll-off at 41 keV. The measured flux in the 2-10 keV energy band is $2.18 \pm0.13 \times10^{-11}$ erg cm-2 s-1 deg-2 in the 2-10 keV band. Combining Swift-XRT with Swift-BAT (15-200 keV) we find that, in the 1.5-200 keV band, the CXRB spectrum can be well described by two smoothly-joined power laws with the energy break at $29.0\pm0.5$ keV corresponding to a $\nu F_{\nu}$ peak located at $22.4\pm0.4$ keV. Conclusions. Taking advantage of both the Swift high energy instruments (XRT and BAT), we produce an analytical description of the CXRB spectrum over a wide (1.5-200 keV) energy band. This model is marginally consistent with the HEAO1 measurement (~10% higher) at energies higher than 20 keV, while it is significantly (30%) higher at low energies (2-10 keV).
Lafora disease (LD) and adult polyglucosan body disease (APBD) are glycogen storage diseases characterized by a pathogenic buildup of insoluble glycogen. Mechanisms causing glycogen insolubility are ...poorly understood. Here, in two mouse models of LD (Epm2a−/− and Epm2b−/−) and one of APBD (Gbe1ys/ys), the separation of soluble and insoluble muscle glycogen is described, enabling separate analysis of each fraction. Total glycogen is increased in LD and APBD mice, which, together with abnormal chain length and molecule size distributions, is largely if not fully attributed to insoluble glycogen. Soluble glycogen consists of molecules with distinct chain length distributions and differential corresponding solubility, providing a mechanistic link between soluble and insoluble glycogen in vivo. Phosphorylation states differ across glycogen fractions and mouse models, demonstrating that hyperphosphorylation is not a basic feature of insoluble glycogen. Lastly, model-specific variances in protein and activity levels of key glycogen synthesis enzymes suggest uninvestigated regulatory mechanisms.
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•Soluble glycogen content and structure: WT-like in Epm2a−/−, Epm2b−/−, Gbe1ys/ys mice•Glycogen hyperphosphorylation is not a general feature of insoluble glycogen•Abnormal chain length and molecule size distributions are limited to insoluble glycogen•Wild-type glycogen molecules vary in average chain length and precipitation propensity
EPM2A, EPM2B, or GBE1 deficiency causes insoluble glycogen accumulation and neurodegenerative diseases. Sullivan et al. show that these defects do not impair the construction of WT-like soluble glycogen. Demonstrating varying chain length distributions and correlating precipitation propensity among WT-glycogen molecules, a mechanistic explanation emerges for the structural characteristics of insoluble glycogen.
•Vasomotor symptoms in postmenopausal women correlate with insomnia and depression.•Postmenopausal insomnia is best managed with menopausal hormone therapy and cognitive behavioral therapy.•Selective ...serotonin (SSRIs) and dual (SNRIs) reuptake inhibitors are also indicated for postmenopausal insomnia with vasomotor symptoms.•Continuous positive airway pressure and mandibular advancement devices improve cardiovascular outcome in postmenopausal women.
Insomnia, vasomotor symptoms (VMS) and depression often co-occur after the menopause, with consequent health problems and reductions in quality of life. The aim of this position statement is to provide evidence-based advice on the management of postmenopausal sleep disorders derived from a systematic review of the literature. The latter yielded results on VMS, insomnia, circadian rhythm disorders, obstructive sleep apnea (OSA) and restless leg syndrome (RLS). Overall, the studies show that menopausal hormone therapy (MHT) improves VMS, insomnia, and mood.
Several antidepressants can improve insomnia, either on their own or in association with MHT; these include selective serotonin reuptake inhibitors (SSRIs), serotonin and norepinephrine reuptake inhibitors (SNRIs), and mirtazapine. Long-term benefits for postmenopausal insomnia may also be achieved with non-drug strategies such as cognitive behavioral therapy (CBT) and aerobic exercise. Continuous positive airway pressure (CPAP) and mandibular advancement devices (MADs) both reduce blood pressure and cortisol levels in postmenopausal women suffering from OSA. However, the data regarding MHT on postmenopausal restless legs syndrome are conflicting.
ABSTRACT
We report on the short- and long-term X-ray properties of the bright nearby Seyfert 2 galaxy NGC 2992, which was extensively observed with Swift, XMM–Newton, and NuSTAR. Swift targeted the ...source more than 100 times between 2019 and 2021 in the context of two monitoring campaigns. Both time-averaged and time-resolved analyses are performed, and we find that the short-to-long term spectral properties of NGC 2992 are dominated by a highly variable nuclear continuum. The source varied in the 2–10 keV energy band from 0.6 to 12 × 10−11 erg cm−2 s−1 during the two year long Swift monitoring. The fastest 2–10 keV flux change (by a factor of $\sim 60{{\ \rm per\ cent}}$) occurred on a time-scale of a few hours. The overall emission spectrum of the source is consistent with a power law-like continuum (Γ = 1.69 ± 0.01) absorbed by a constant line-of-sight column density NH = (7.8 ± 0.1) × 1021$\rm cm^{-2}$. The reflected emission is likely due to matter with an average column density NH = (9.6 ± 2.7) × 1022$\rm cm^{-2}$, thus NGC 2992 appears to have a globally Compton-thin circumnuclear medium. This scenario is fully supported by an independent analysis of the fractional variability and by XMM–Newton multiyear spectra.
Context.Many of the extragalactic sources detected in γ rays at TeV energies are BL Lac objects. In particular, they belong to the subclass of “high frequency peaked BL Lacs” (HBLs), as their ...spectral energy distributions exhibit a first peak in the X-ray band. At a closer look, their X-ray spectra appear to be generally curved into a log-parabolic shape. In a previous investigation of Mrk 421, two correlations were found between the spectral parameters. One involves the height Sp increasing with the position Ep of the first peak; this was interpreted as a signature of synchrotron emission from relativistic electrons. The other involves the curvature parameter b decreasing as Ep increases; this points toward statistical/stochastic acceleration processes for the emitting electrons. Aims.We analyse X-ray spectra of several TeV HBLs to pinpoint their behaviours in the $E_{\rm p}-S_{\rm p}$ and $E_{\rm p}-b$ planes and to compare them with Mrk 421. Methods.We perfom X-ray spectral analyses of a sample of 15 BL Lacs. We report the whole set of observations obtained with the BeppoSAX, XMM-Newton and Swift satellites between 29/06/96 and 07/04/07. We focus on five sources (PKS 0548-322, 1H 1426+418, Mrk 501, 1ES 1959+650, PKS 2155-304) whose X-ray observations warrant detailed searching of correlations or trends. Results.Within our database, we find that four out of five sources, namely PKS 0548-322, 1H 1426+418, Mrk 501 and 1ES 1959+650, follow similar trends as Mrk 421 in the $E_{\rm p}-S_{\rm p}$ plane, while PKS 2155-304 differs. As for the $E_{\rm p}-b$ plane, all TeV HBLs follow a similar behaviour. Conclusions.The trends exhibited by Mrk 421 appear to be shared by several TeV HBLs, such as to warrant discussing predictions from the X-ray spectral evolution to that of TeV emissions.
Lafora disease (LD) is a fatal progressive epilepsy essentially caused by loss‐of‐function mutations in the glycogen phosphatase laforin or the ubiquitin E3 ligase malin. Glycogen in LD is ...hyperphosphorylated and poorly hydrosoluble. It precipitates and accumulates into neurotoxic Lafora bodies (LBs). The leading LD hypothesis that hyperphosphorylation causes the insolubility was recently challenged by the observation that phosphatase‐inactive laforin rescues the laforin‐deficient LD mouse model, apparently through correction of a general autophagy impairment. We were for the first time able to quantify brain glycogen phosphate. We also measured glycogen content and chain lengths, LBs, and autophagy markers in several laforin‐ or malin‐deficient mouse lines expressing phosphatase‐inactive laforin. We find that: (i) in laforin‐deficient mice, phosphatase‐inactive laforin corrects glycogen chain lengths, and not hyperphosphorylation, which leads to correction of glycogen amounts and prevention of LBs; (ii) in malin‐deficient mice, phosphatase‐inactive laforin confers no correction; (iii) general impairment of autophagy is not necessary in LD. We conclude that laforin's principle function is to control glycogen chain lengths, in a malin‐dependent fashion, and that loss of this control underlies LD.
Synopsis
Abnormal glycogen chain length distribution strictly correlates with glycogen accumulation and Lafora body (LB) formation in Lafora disease (LD). Against current hypotheses, neither glycogen hyperphosphorylation nor deficient general autophagy are prerequisites of the disease.
By methodological advances chain length distribution (CLD) and phosphorylation of glycogen were determined in brain tissue confirming that overexpressed wild‐type laforin corrects the molecular phenotype in an LD mouse model.
Phosphatase‐inactive laforin does not correct glycogen hyperphosphorylation in malin‐ and laforin‐deficient mice and prevents abnormal CLD and accumulation of glycogen as well as LB formation.
Prevention of abnormal chain length distribution and accumulation of brain glycogen as well as LB formation by phosphatase‐inactive laforin is malin‐dependent as no rescue occurs in malin‐deficient mice.
General impairment of autophagy is not necessary in LD as markers of autophagic flux are not changed in any of our LD mouse models.
Laforin controls glycogen chain length distribution in a malin‐dependent fashion, and lack of this control leads to abnormal glycogen structure, glycogen accumulation, LB formation, hence to LD.
Abnormal glycogen chain length distribution strictly correlates with glycogen accumulation and Lafora body (LB) formation in Lafora disease (LD). Against current hypotheses, neither glycogen hyperphosphorylation nor deficient general autophagy are prerequisites of the disease.
The 10 mm incisions used in minimally invasive cancer surgery prevent the direct palpation of internal organs, making intraoperative tumor localization difficult. A tactile sensing instrument (TSI), ...which uses a commercially available sensor to measure distributed pressure profiles along the contacting surface, has been developed to facilitate remote tissue palpation. The objective of this research is to assess the feasibility of using the TSI under robotic control to reliably locate underlying tumors while reducing collateral tissue trauma. The performance of humans and a robot using the TSI to locate tumor phantoms embedded into ex vivo bovine livers is compared. An augmented hybrid impedance control scheme has been implemented on a Mitsubishi PA10-7C to perform the force/position control used in the trials. The results show that using the TSI under robotic control realizes an average 35% decrease in the maximum forces applied and a 50% increase in tumor detection accuracy when compared to manual manipulation of the same instrument. This demonstrates that the detection of tumors using tactile sensing is highly dependent on how consistently the forces on the tactile sensing area are applied, and that robotic assistance can be of great benefit when trying to localize tumors in minimally invasive surgery.
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