ABSTRACT
We report the discovery of two apparently isolated stellar remnants that exhibit rotationally modulated magnetic Balmer emission, adding to the emerging DAHe class of white dwarf stars. ...While the previously discovered members of this class show Zeeman-split triplet emission features corresponding to single magnetic field strengths, these two new objects exhibit significant fluctuations in their apparent magnetic field strengths with variability phase. The Zeeman-split hydrogen emission lines in LP 705−64 broaden from 9.4 to 22.2 MG over an apparent spin period of 72.629 min. Similarly, WD J143019.29−562358.33 varies from 5.8 to 8.9 MG over its apparent 86.394 min rotation period. This brings the DAHe class of white dwarfs to at least five objects, all with effective temperatures within 500 K of 8000 K and masses ranging from $0.65\,\,{\text{to}}\,\,0.83\, {\rm M}_{\odot }$.
In 2012, five high-school students involved in the Pulsar Search Collaboratory discovered the millisecond pulsar (MSP) PSR J1400−1431, and initial timing parameters were published in Rosen et al. a ...year later. Since then, we have obtained a phase-connected timing solution spanning five years, resolving a significant position discrepancy and measuring , proper motion, parallax, and a monotonic slope in dispersion measure over time. Due to PSR J1400−1431's proximity and significant proper motion, we use the Shklovskii effect and other priors to determine a 95% confidence interval for PSR J1400−1431's distance, pc. With an improved timing position, we present the first detection of the pulsar's low-mass white dwarf (WD) companion using the Goodman Spectrograph on the 4.1 m SOAR telescope. Deeper imaging suggests that it is a cool DA-type WD with K and . We show a convincing association between PSR J1400−1431 and a γ-ray point source, 3FGL J1400.5−1437, but only weak (3.3 ) evidence of pulsations after folding γ-ray photons using our radio timing model. We detect an X-ray counterpart with XMM-Newton, but the measured X-ray luminosity (1×1029 erg s−1) makes PSR J1400−1431 the least X-ray luminous rotation-powered MSP detected to date. Together, our findings present a consistent picture of a nearby ( pc) MSP in a 9.5-day orbit around a cool ∼0.3 M WD companion, with orbital inclination .
Observations of debris disks, the products of the collisional evolution of rocky planetesimals, can be used to trace planetary activity across a wide range of stellar types. The most common end ...points of stellar evolution are no exception, as debris disks have been observed around several dozen white dwarf stars. But instead of planetary formation, post-main-sequence debris disks are a signpost of planetary destruction, resulting in compact debris disks from the tidal disruption of remnant planetesimals. In this work, we present the discovery of five new debris disks around white dwarf stars with gaseous debris in emission. All five systems exhibit excess infrared radiation from dusty debris, emission lines from gaseous debris, and atmospheric absorption features indicating ongoing accretion of metal-rich debris. In four of the systems, we detect multiple metal species in emission, some of which occur at strengths and transitions previously unseen in debris disks around white dwarf stars. Our first year of spectroscopic follow-up hints at strong variability in the emission lines that can be studied in the future, expanding the range of phenomena these post-main-sequence debris disks exhibit.
Summary
Background
Insulin dysregulation, obesity, and exposure to high‐nonstructural carbohydrate (NSC) forage are risk factors for equine metabolic syndrome‐associated laminitis (EMSAL); high ...systemic insulin concentrations in EMSAL are proposed to induce cellular dysregulation in the digital lamellae through activation of the insulin‐like growth factor‐1 receptor.
Objectives
To use a dietary challenge model (DCM) and a euglycaemic–hyperinsulinaemic clamp (EHC) model to assess lamellar growth factor‐related signalling.
Study design
Lamellar phospho (P)‐protein concentrations of signalling proteins important in growth factor‐related signalling were assessed in 2 models: 1) lean and obese ponies on a low‐ or high‐NSC diet; and 2) EHC model using Standardbred horses.
Methods
Ponies stratified for body condition (lean LN, n = 11 and obese OB, n = 11) were exposed to a low‐NSC diet (LO, n = 5 per group for LN LO and OB LO) or a high NSC diet (HI, n = 6 per group for LN HI and OB HI groups) for 7 days. For the EHC model, horses were administered insulin (constant rate infusion 6 mIU/kg bwt/min combined with 50% dextrose, EHC group, n = 8) or saline (0.57 mL/kg bwt/h, CON group, n = 8) for 48 h. Immunoblotting was employed to assess concentrations of activated/phosphorylated and total protein for members of the PI3K/Akt/mTORC1 and Ras/ERK pathways in lamellar samples from both models.
Results
In the DCM, lamellar P‐(Ser 240/244) RPS6 was increased in OB HI ponies (vs. OB LO, P<0.05); positive correlations existed (P<0.05; r>0.5) between Day 7 basal serum insulin concentrations and lamellar concentrations of P‐p70S6K and P‐(Ser 240/244) RPS6. In the EHC model, lamellar concentrations of P‐Akt, P‐p70S6K, P‐ERK 1/2, P‐p90RSK, and both P‐(Ser 235/236) and P‐(Ser 240/244) RPS6 were increased in the EHC group (vs. CON, P<0.05).
Main limitations
The primary limitations of this study are the small number of animals per group in the DCM study, and the fact that many animals did not develop laminitis as that was not the endpoint of either study.
Conclusions
These results support further investigation of mTORC1/RPS6 signalling as a potential therapeutic target(s) in EMSAL.
The Summary is available in Chinese – see Supporting Information.
Summary
Climate change is a real and accelerating existential danger. Urgent action is required to halt its progression, and everyone can contribute. Pollution mitigation represents an important ...opportunity for much needed leadership from the health community, addressing a threat that will directly and seriously impact the health and well‐being of current and future generations. Inhalational anaesthetics are a significant contributor to healthcare‐related greenhouse gas emissions and minimising their climate impact represents a meaningful and achievable intervention. A challenge exists in translating well‐established knowledge about inhalational anaesthetic pollution into practical action. CODA is a medical education and health promotion charity that aims to deliver climate action‐oriented recommendations, supported by useful resources and success stories. The CODA‐hosted platform is designed to maximise engagement of the global healthcare community and draws upon diverse experiences to develop global solutions and accelerate action. The action guidance for addressing pollution from inhalational anaesthetics is the subject of this article. These are practical, evidence‐based actions that can be undertaken to reduce the impact of pollution from inhalational anaesthetics, without compromising patient care and include: removal of desflurane from drug formularies; decommissioning central nitrous oxide piping; avoidance of nitrous oxide use; minimising fresh gas flows during anaesthesia; and prioritising total intravenous anaesthesia and regional anaesthesia when clinically safe to do so. Guidance on how to educate, implement, measure and review progress on these mitigation actions is provided, along with means to share successes and contribute to the essential, global transition towards environmentally sustainable anaesthesia.
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