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2025
Abstract
Comets and asteroids have long captured human curiosity, and until recently, all documented examples belonged to our Solar System. That changed with the discovery of the first known interstellar object, 1I/2017 U1 (‘Oumuamua), in 2017. Two years later, on August 30, 2019, Gennady Borisov discovered a second interstellar object, 2019 Q4, which was officially designated 2I/Borisov. From its initial images, the object’s diffuse appearance hinted at its cometary nature. To better understand the photometric evolution of comet 2I/Borisov as it traveled through the inner Solar System, we compiled observations using medium-sized telescopes. This data is crucial for gaining insights into its size and composition, as well as how such objects, after millions of years in interstellar space, behave when exposed to the Sun’s radiation. Given that 2I/Borisov is the first interstellar comet ever observed, constraining its behavior is of great scientific interest. In this paper, we present photometric data gathered from observatories in Crimea and Catalonia, highlighting the importance of systematic photometric studies of interstellar objects using meter-class telescopes. Our observations showed a steady increase in the comet’s brightness as it approached perihelion, likely due to the slow sublimation of ices. Over the five-month pre-perihelion observation period, we did not detect any significant changes in magnitude. The analysis of observations reveals a steady increase in comet 2I/Borisov brightness as it approached perihelion, likely due to the sublimation of ices, with no observable outbursts during the five-month pre-perihelion period. Additionally, we discuss the challenges in ground-based observation of comets posed by light pollution today, particularly in urban areas, where visual observations are severely limited. Using sample surface brightness measurements, we demonstrate the impact of light pollution and outline the importance of systematic photometric studies for interstellar objects.- Book : 370(4)
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2025
AbstractHuman norovirus (HNoV) and human adenovirus (HAdV) are major causes of acute viral gastroenteritis globally and environmentally transmitted via the faecal-oral route through contaminated food and water. Recent evidence of these enteric viruses residing within environmental free-living amoebae (FLA)—specifically Vermamoeba vermiformis, Acanthamoeba polyphaga, and Willaertia magna—has significant implications for environmental virology and public health. The incorporation of HNoV into the cytoplasm and vacuoles of V. vermiformis and A. polyphaga, as well as the nuclear localization of HAdV within W. magna, was demonstrated using quantitative PCR and fluorescence microscopy. Intact HNoV and HAdV virions persisted inside FLA trophozoites, cysts, and extracellular vesicles for up to 12 days. Moreover, HAdV retained infectivity in buffalo green monkey kidney cells following intracellular persistence, suggesting these viruses can evade amoebal digestion and structural degradation. In the case of HAdV, nuclear incorporation, preservation of capsid integrity, and detection of mRNA associated with adenoviral fiber protein synthesis further suggest the possible initiation of virus-related transcriptional activity within the amoeba host.These findings challenge current assumptions about virus removal rates in sewage treatment, food safety protocols, and drinking water production. The enhanced persistence and protection conferred by FLA may also impact microbial risk assessments for recreational water use, particularly in sewage-impacted rivers and lakes. Recognition of FLA as reservoirs and transport vessels for enteric viruses necessitates a re-evaluation of existing water and sanitation guidelines to better mitigate environmental transmission pathways.Graphical Abstract- Book : ()
- Pub. Date : 2025
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2025
Abstract
Regional scale Marine Cloud Brightening (MCB) has been proposed as a novel climate intervention to reduce the impact of global warming and associated marine heatwaves on the
Great Barrier Reef (GBR). The concept relies on artificially generated sea spray aerosols (SSA) at the ocean surface and their transport in sufficient quantities to low-level maritime clouds. A portion of the SSA that reaches cloud height can act as additional cloud condensation nuclei and modify cloud microphysical properties, potentially reducing the amount of solar radiation reaching the sea surface. Although modelling data supports the MCB concept, field experiments demonstrating the dispersion of artificially produced sea spray aerosols to clouds have not been previously reported. Here, we show that within a field of low-level trade wind cumulus-type clouds, an aerosol plume generated at the sea surface on board a research vessel was rapidly advected to cloud base height. Aircraft measurements conducted during two different sampling strategies, detected the aerosol plume from the vessel’s sea water atomisation system just below cloud bases at 700–900 m altitudes. For an estimated surface level aerosol production rate of 4 × 1014/s, aerosol concentrations at cloud base were detected with peak number concentrations of up to ~1 × 103/cm3. Although such production rates of aerosol particles are orders of magnitude less than what is envisioned for any practical implementation of MCB, our results indicate that cloud perturbation experiments should now be possible using surface-produced sea spray aerosols.- Book : ()
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2025
ABSTRACTIntroductionAboriginal patients face barriers to accessing cancer care. Few studies have evaluated the utilisation of radiotherapy or surgery in Aboriginal people. This study aims at assessing variation in types of cancer, degree of spread (DOS) at presentation, utilisation rates of cancer surgery and radiotherapy between Aboriginal and non‐Aboriginal cancer patients.MethodsRetrospective analysis of de‐identified linked datasets. All patients with registered notifiable cancer in the NSW cancer registry 2009–2018 separated by Aboriginality status were included.ResultsTotally 389,992 people were diagnosed in NSW during study period; 8970 people (2.3%) identified as Aboriginal. In univariate analysis, Aboriginal people presented at diagnosis with statistically significant younger age, greater comorbidity, advanced (DOS) and greater proportions living in most disadvantaged areas than non‐Aboriginal people. Based on univariate analysis, Aboriginal patients received radiotherapy more frequently than non‐Aboriginal patients (30.3% versus 26.0%, p < 0.01). Non‐Aboriginal patients underwent cancer surgery more frequently than Aboriginal patients (57.0% versus 51.2%, p < 0.01). When stratified by tumour type and adjustment for patient and clinical factors, radiotherapy and surgery utilisation varied by type of cancer.ConclusionsThe degree of cancer spread, and the presence of comorbidities remains a greater issue for Aboriginal people. Access to radiotherapy increased significantly for Aboriginal patients during the past 10 years. However, differences in surgical and radiotherapy utilisation exist. These differences can be partially explained by the greater DOS and presence of comorbidity in Aboriginal patients leading to less surgical intervention and greater requirement for radiotherapy.- Book : ()
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2025
Abstract
We present the analysis of Lyα haloes around faint quasars at z ∼ 4 and z ∼ 6. We use 20 and 162 quasars at z ∼ 4 and z ∼ 6, taken by slit spectroscopy, and detect Lyα haloes around 12 and 26 of these quasars, respectively. The average absolute magnitudes of the detected quasars are 〈M1450〉 = −23.84 mag at z ∼ 4 and 〈M1450〉 = −23.68 mag at z ∼ 6, which are comparable at z ∼ 4 and 3 mag fainter at z ∼ 6 than those of previous studies. The median surface brightness profiles are found to be consistent with an exponential curve, showing a hint of flattening within a radius of 5 kpc. The Lyα haloes around these faint quasars are systematically fainter than those around bright quasars in the previous studies. We confirm the previous results that the Lyα halo luminosity depends on both the ionizing and Lyα peak luminosities of quasars at z ∼ 4, and also find that a similar correlation holds even at z ∼ 6. While the observed Lyα halo luminosity is overall attributed to recombination emission from the optically thin gas clouds in the CGM, its luminosity dependences can be consistently explained by the partial contributions of recombination radiation from the optically thick clouds, which is thought to originate from the CGM centre, and the scattered Lyα photons, which is resonantly trapped at the CGM centre and escaping outside of the haloes.- Book : ()
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2025
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2025
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2025
Abstract
The eigen-mode structure and distribution associated with the global dispersion are studied based on linear gyro-kinetic simulations in a global toroidal geometry using parameters and profiles modeled for JT-60U-like discharges with a strongly reversed magnetic shear configuration, which exhibit L-mode characteristics subject to a strong profile constraint. By incorporating the mode mismatch parameter ∆μ, related to the parallel wave number k_∥ (≡Δμ⁄R_0 ), and also the slab-to-toroidal ratio parameter X(≡(k_∥ R_0)⁄(k_θ ρ_i )), we identified two qualitatively distinct unstable branches. One is the density gradient driven trapped electron modes (∇n-TEMs) influenced by the ion temperature gradient with lower toroidal mode numbers n, while transited to weak toroidal-like ion temperature gradient modes (ITG modes) as n increases, in the inner negative magnetic shear region (s ̂<0). The other is the slab-like ITG modes with higher-n in the outer minimum safety factor region (q~q_min). These dynamics result in the separate radial location of the density and ion/electron temperature gradients, i.e. the former is inner region while the latter is outer region. These two branches are weakly connected through the boundary region inside the q_min surface, which leads to a discontinuity in the quasi-linear flux. Each branch is found to show approximately the similar level of peak growth rate in inner and outer regions, indicating that the constrained profiles are expected to be established such that linearly unstable free energy sources are globally balanced so as to maintain such profile in a quasi-steady state with a self-organized manner without causing unbalanced transport.- Book : ()
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2025
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